bluuebunny/crossref_metadata_2025 huggingface dataset:
Mineralogical Notes from Torreon, State of Chihuahua, Mexico
Authors: Collins Henry F.
Published: December 2006

In the early part of 1890 I noticed in some of the workings of the Torreon Mines, and chiefly on a decomposed ehalcopyrite or in close connection therewith, a greenish-blue to sky-blue lamellar coating about inch in thickness, with sometimes isolated plumose groups of scaly crystals having a pearly lustre. Both appearance and mode of occurrence of the mineral led me to think it a basic sulphate of Copper, probably cyanotriehite, or possibly a new species. Soon afterwards however, it was noticed that when the ore, as sorted for smelting, contained any quantity of the pale blue incrustation the cyanide assay failed to give accurate results in the estimation of copper, and on testing such ore qualitatively for zinc quite an appreciable quantity was found. Want of leisure prevented a more extended examination, but a good many specimens were selected and carefully preserved.
On some examples of Cone-in-Cone Structure
Authors: Cole Grenville A. J.
Published: December 2006

Probably everyone who has considered the arrangement of the constituents of an aggregate composed of radially grouped fibres has realised that the individual fibres are conical or pyramidal in form, their apices meeting in the centre of the aggregate. In a coarse example of this mode of erystallisation, such as the calcite concretions in the magnesian limestone of Durham, this conical form of the constituent crystals is very easily seen; the cones cleave across, where composed of a cleavable mineral, showing that the particles composing them have the same orientation within the limits of the cone, and that each cone, in fact, is a crystal, bounded ultimately by contact with its neighbours.
Note on a Crystal of Tourmaline
Authors: Lewis W. J.
Published: December 2006

My friend, Mr. A. T. Karslake, sent me recently a pareel of crystals from Ceylon, amongst which was a brown tourmaline showing the very rare face z =, (first recorded by Haüy), on whose existence so much doubt has been thrown. The crystal is about ½ inch across, and about ¼ inch in the direction of the axis, and shows well the hemimorphic development. At the analogous pole are r{100} and z, both largely developed, also o {111}, e {110}, s, .
Note on a peculiar occurrence of Galena
Authors: Stuart Thomson J.
Published: December 2006

Some time ago I was informed that galena was being obtained in a sandstone quarry at Aimville, about two-and-a-half miles north of Kirknewton, which had been recently re-opened for the purpose of supplying building material in connection with the extension of the Harperrig Reservoir, belonging to the Edinburgh Water Trust. As I saw no likelihood of my soon being able personally to visit the spot, I mentioned the fact to my friend, Mr. Alex. Lumsden, M.E., who I knew had sometimes occasion to pass near the locality, at the same time telling him that I did not attach much importance to the alleged occurrence, and that I did not expect that it would be of such interest as to be worthy of a special visit. Subsequent investigation showed, however, that I was mistaken, and as the mode of occurrence of the mineral is so unusual, some account of it may not be without interest.
On Baddeleyite (native zirconia), a new Mineral, from Rakwana, Ceylon
Authors: Fletcher L.
Published: December 2006

Shortly after the Meeting of June 16th, at which Mr. Dick gave the description of the characters of Geikielite, Mr. Joseph Baddeley, who had brought the specimens from Rakwana (or Rackwanné) (80°40' E., 6°25' N., in the District of Kollonnagam, Ceylon), courteously offered to present one of them to the British Museum for preservation in the Mineral Collection: the rest of his small store of eight or nine stones, picked out by him from a heap of other dense pebbles, he required for sending as samples to those friends in Ceylon whom he wished to interest in a search for further material.
Binnite from Imfeld in the Binnenthal
Authors: Trechmann C. O.
Published: December 2006

This rare mineral, the Dufrenoysite of yon Waltershausen and others, crystallising in the cubical system, has been made the subject of careful investigation by several observers, with the result that, up to the present moment, it is doubtful whether the character of its forms is holohedral or hemihedral with inclined faces. Hessenberg found that the mineral crystallised holohedrally, but Groth, confirming Kenngott's view, states that the best crystal in the Strassburg University collection shows a distinctly hemihedral development.
Notes on the optical characters of the Globules and Spherulites of Lithium Phosphate and some other salts
Authors: McMahon C. A.
Published: December 2006

In my paper "On the Micro-chemical Analysis of Rock Making Minerals, '' I noticed the abnormal behaviour of globules of lithium phosphate Li3PO4 + H2O in polarised light; the dark cross which ought to remain fixed when the globule is revolved between crossed nicols, opening up, in some cases, into two hyperbolic branches like those of a biaxial crystal in converging polarised light. I find that similar ano. malous results may be obtained from the globules yielded by other salts; as for example those of the double sulphates of beryllium and potassium (BeSO4K2SO4 + 2H2O), and of lithium and sodium (LiNaSO4).
Extinction-Angles in Cleavage-Flakes
Authors: Harker Alfred
Published: December 2006

Now that the measurement of extinction-angles in cleavage-flakes is frequently used to assist in the identification of minerals, the question of the relation of angles so measured to the orientation of the optic axes is one that must frequently arise. I confine myself here to the case of monoclinic minerals, such as hornblende and augxte, in which the optic axes are parallel to the clinopinacoid and the cleavage is prismatic.
On the mode of occurrence of Gold
Authors: Louis Henry
Published: December 2006

In the present paper an attempt will be made to summarise known facts respecting the mode of occurrence of gold in its matrix, and to draw certain inferences from these facts as to the manner in which the gold has been deposited. The general opinion of miners that it has been introduced by igneous action, in a state of either fusion or volatilization, does not agree with modern theories of the origin of metalliferous veins, which ascribe their existence to hydrothermal action, or at any rate suppose the metals to have been introduced in aqueous solution.
Spangolite
Authors: Miers H. A.
Published: December 2006

In the year 1890 Mr. S. L. Penfield described a new copper mineral, to which he gave the name of Spangolite in honour of Mr. Norman Spang, by whom it was first brought to his notice. Of this beautiful mineral only a single specimen was found, and the exact locality has never been ascertained; it belonged to a man living near Tombstone in Arizona, who had gathered together a collection of minerals within a radius of about 200 miles, and it is described by Mr. Penfield as " a rounded mass of impure euprite which was mostly covered with hexagonal crystals of Spangolite associated with a few crystals of azurite and some slender prismatic crystals of a copper mineral containing chlorine, probably atacamite."
Note on a Zircon from Expailly, Haute Loire
Authors: Rutley Frank
Published: December 2006

The great variation which occurs in the specific gravity of zircons seems to render it possible that the presence of fluid and gas inclusions might, to some extent, account for this. A small, partly red, partly eolourless crystal was selected from a number of others all derived from the Riou Pezzoliou, Expailly, near Le Puy, which, when examined under the microscope, was found to contain numerous inclusions, some with, others without bubbles.
A Chemical Study of Some Native Arsenates and Phosphates
Authors: Church A. H.
Published: December 2006

The present series of notes is mainly based upon analyses executed during the years 1867-1877. but these have been supplemented in a few instances by recent work. The series may be regarded as a continuation of several papers published from time to time in the Journal of the Chemical Society, in the Chemical News, and in the Proceedings of the Royal Irish Academy. Throughout these inquiries particular attention has been paid to the degree of tenacity with which the water present in the hydrous species is held.
A Basic Ferric Sulphate, from Parys Mount, Anglesey
Authors: Church A. H.
Published: December 2006

An orange-coloured ochreous substance from Parys Mount, Anglesey, was recently submitted to analysis.

The observed loss of water at 100°C corresponds to 4H2O, which requires 13.24 percent.
Augelite
Authors: Prior G. T. , Spencer L. J.
Published: December 2006

Augelite was one of several aluminium phosphates from the iron mine of Westanå, Skåne, Sweden, described by C. W. Blomstrancl in 1868 (Öfv. Ak. Förh. Stockh. XXV. 1868, p. 199). He states it to be a massive mineral with distinct cleavages in three directions, and names it augelite (avγη lustre) on account of the strong pearly lustre on the cleavage ṡurfaces. He determines its specific gravity as 2.77, and, as the result of his analyses, represents its chemical composition by the formula, 2Al2O3. P2O5. 3H2O. Since this paper of Blomstrand, as far as we are aware, no further reference to augelite has been made, and, since hitherto distinct crystals of the mineral have not bhen found, its position as a definite species seems to have been regarded as somewhat doubtful, for we find that Dana, in the last edition of the System of Mineralogy, includes it in a rather unsatisfactory group of more or less doubtful species appended to evansite.
A Note on Cone-in-Cone Structure
Authors: Bonney T. G.
Published: December 2006

The structure called cone-in-cone attracted my attention when I was working at certain forms of jointing and spherulitic structures in rocks, and has been studied in a desultoiy fashion ever since. Moreover, the Museum of University College possesses some good specimens of cone in-cone obtained by the late Prof. Morris, and I received a present of others, which had been used by Mr. W. S. Gresley for his suggestive paper when he left England for America. But though I formed some general conclusions on the subject, I abstained from writing, because I felt doubt concerning one point of importance, and had never seen a good example of cone-in-cone in the field.
On the Occurrence of Delessite in Cantyre
Authors: Heddle  , Thomson Stuart
Published: December 2006

Delessite is of much rarer occurrence in Scotland than saponite, and moreover it is by no means so characteristic in its appearances. Its modes of occurrence are much the same, only it is much less frequently the tenant of drases, affecting rather rents or fissures, and in these last it frequently goes to form what may be called a " composite vein." This may be filled for the most pȧrt with fibrous calcite, transversely disposed, and the reopening of the fissure is disclosed by the delessite, which, after lining one side of the vein for some distance, suddenly crosses the fibres of the calcite diagonally, and lies between i~ and the rock upon the opposite side.
On the Structure-Planes of Corundum
Authors: Judd John W.
Published: December 2006

While examining the fine series of corundums brought from Burma by Mr. C. Barrington Brown, F.G.S., and comparing them with specimens obtained from Ceylon, Southern India, the United States. and other localities, I have been led to devote especial attention to the curious " parting-planes " which are sometimes found in crystals of this mineral, but which, in other cases, appear to be entirely wanting. In making these comparisons, I have had the great advantage of being able to refer to the fine collection of corundums in the British Museum (Natural History) at South Kensington, and have to gratefully acknowledge the advice and assistance which have been so freely afforded to me at all times by Mr. Fletcher and Mr. Miers.
On Some Simple Massive Minerals (Crystalline Rocks) from India and Australia
Authors: Judd John W.
Published: December 2006

In recent years, the respective provinces of Mineralogy and Petrography have become much more clearly defined than was formerly the case. We no longer include uncrystallised substances, like obsidian, taehylyto and coals among mineral species; and, on the other hand, we recognise the fact that many materials originally analysed and treated as homogeneous—such as lapis-lazuli, emery, and many similar materials—are really mineral aggregates or rocks, and thus come within the domain of the petrographer. This last advantage has been one of the most important of those which have resulted from the application of the microscope to the study of inorganic bodies.
On Homogeneous, Structures and the Symmetrical Partitioning of them, with Application to Crystals
Authors: Barlow William
Published: December 2006

The above investigation shows:—

1.

The nature of homogeneity of structure, and the properties which distinguish it from structureless homogeneity. The new definition of a homogeneous structure recently put forward by the author in Groth's Zeitschrift is given.

2.

A method of realising in a concrete form, and with great generality, the kind of repetition in space which constitutes homogeneity of structure, the models employed for this purpose each consisting of a number of similar plaster hands appropriately arranged in space.

The total number of types of arrangement, all of which can be represented in this way, is 230, this being the number of typical point systems described by Fedorow and Schönflies, derived by their extension of Sohncke's methods. The various types of homogeneous structure, like the corresponding point-systems, all fall into the 32 classes of crystal symmetry.

3.

What property common to all homogeneous structures whatever most nearly coyresponds to Thomson and Tait's definition of homogeneity.

4.

Reasons for regarding as untenable the arguments put forward by Fedorow in support of his recent attempt to select from among the types of homogeneous structure those which are possible for crystals, and to determine the shapes of their ultimate units.

5.

The possibility of so classifying all conceivable ways of symmetrically partitioning all the types of homogeneous structure as to avoid all reference to the nature of the cell-faces, whether plane or otherwise, and, in other respects also, be perfectly general. Some reasons for undertaking this classification, notwithstanding its complexity, are given, the chief one being the relation of symmetrical partitioning to some stereo-chemical and other experimental facts.
On the Humite Series
Authors: Lewis W. J.
Published: December 2006

The humite series has formed one of the most interesting problems to mineralogists ever since Scacchi established the three types. I may, perhaps, recall that he found the crystals to be divisible into three classes, all capable of representation by reference to a common parametral plane and three zone-axes at right angles to one another. But the three classes differ in the following respects:--(1) Each has a peculiar set of faces, and, with the exception of the pinakoids and the actual or theoretical prisms, few of the forms coincide in different types. (2) Whilst all the faces on crystals of one class can be easily represented by quite simple indices, such as (111) (123) (103) by a judicious selection of one of its faces as parametral plane, the faces on crystals of the remaining two classes give for the same parameters very high and complicated indices.
Notes on a Biotite-Cyanite-Cordierite-rock from the Upper Satlej Valley, N.W. Himalayas
Authors: McMahon C. A.
Published: December 2006

Some years ago I found in the bed of the Satlej at Wangtu, in the N.W. Himalayas, about 80 miles, as the crow flies, north-east of Simla, a boulder of the rock described in the following pages, It is composed of biotite, cyanite and cordierite, with apatite and rutile as accessory minerals.

The specimen has a specific gravity of 2.92. Its structure is holocrystalline, and its minerals show no trace of parallelism in their orientation. It is, I think, a product of contact metamorphism.
Note on the Occurrence of Rocks Allied to Monchiquite in the Island of Fernando Noronha
Authors: Prior G. T.
Published: December 2006

The name of Monehiquite, first applied by Rosenbusch and Hunter (Tscherm. Min. Mitth. XI. 1890, p. 445) to a peculiar group of dyke rocks tound in association with elæolite syenite in Brazil, is rapidly becoming familial" to petrologists through the discovery of similar rocks from various other localities.

The Brazilian Monehiquites were described by Rosenbusch as black to grayish-black rocks, consisting of porphyritic ohvine and pyroxene, with widely varyiug amounts of hornblende and mica, in a glassy base usually crowded with hornblende microliths.
The “Satin Spar” of Alston in Cumberland; and the Determination of Massive and Fibrosus Calcites and Aragonites
Authors: Spencer L. J.
Published: December 2006

Owing to the fact that aragonite frequently occurs in fibrous aggregations, as in "flos ferri,' it seems to have been sometimes assumed that all fibrous specimens of calcium carbonate are aragonite.

On these grounds the " satin spar" from Mston Moor in Cumberland is often referied to aragonite, although it has more than once been shown to be really calcite. Miller refers to it under aragonite, as being from "Dufton in Cumberland, '' saying that it contains 4.25 per cent. of manganese carbonate: these figures are those given by J. Holme in a very crude analysis of the satin spar of Alston.
Zinckenite and Wolfsborgite (Chalcostibite) from Wolfsberg in the Harz; and the Zinckenite Group
Authors: Spencer L. J.
Published: December 2006

Although zinekenite and wolfsbergite are to be considered as isomorphous, it seems to be as rare a thing to find simple crystals of zinekenite as it is to find twinned crystals of wolfsbergite. In the following note simple and twinned crystals of the two minerals respectively are described.
The Crystallography of Plagionite: New Crystal Forms on Stephanite, Enargite and Anglesite
Authors: Spencer L. J.
Published: December 2006

On the British Museum specimens of plagionite from Wolfsberg, in the Harz, all the well-established crystal forms previously recorded have been detected.
An Occurrence of Prehnite in Wales
Authors: Harrison W. Jerome
Published: December 2006

The little land-locked harbour of Pwllheli in Caernarvonshire owes its existence to a boss of igneous rock, which forms a natural breakwater, and which is known in Wales as the " Gimlet Rock."

The large quarries afford excellent exposures of the rock, which is worked into " setts " and used largely for paving purposes in the large towns of Lancashire, etc. It is a coarse ophitie dolerite, in which the augite is a very conspicuous mineral. The rock is traversed by many segregation veins, and is much jointed. The faces of the larger jointplanes are covered with crystals of quartz, calcite, a little natrolite, brookite and prehnite. But the three last-named minerals are of rare occurrence, and are always associated with quartz.
Note on Altaite from Burma
Authors: Louis Henry
Published: December 2006

By the kindness of Mr. A. H. Bromly, Manager of the Choukpazat Gold Mining Company's mines at Choukpazat, Wuntho, Upper Burma, I have received a few hand-samples of the veinstuff from these mines. The vein runs in clay slate or ehloritic slate, parallel apparently to the bedding, with a strike north-east to south-west, and a dip of 20° to 25° to the south. The veinstuff, to judge from the samples submitted to me, consists of white, somewhat saccharoidal quartz, with some calcspar, and contains iron pyrites, alsenieal pyrites, visible free gold (rather pale in colour and apparently rich in silver), and the mineral that forms the subject of the present note.
On Some British Pseudomorphs
Authors: Miers H. A.
Published: December 2006

A specimen in the British Museum, consisting mainly of brown chalybite and decomposed iron pyrites--the latter mostly converted into earthy oxides--bears upon its surfitce and in its cavities a number of thin prisms encrusted with a botryoidal yellowish substance which covers a great part of the decomposed specimen. On close inspection the needles are seen to be Cronstedtite, mostly but not entirely converted into black limonite, and the encrusting substance consists mainly of phosphate (with a little carbonate) of lime. The latter is sometimes crystalline on its surface.
The Identity of Andorite, Sundtite and Webnerite
Authors: Prior G. T. , Spencer L. J.
Published: December 2006

On November 14th, 1892, Prof. J. A. Krenner read before the Hungarian Academy of Sciences an account of a new silver ore from Felsöbánya, to which he gave the name of Andofite. It was described as orthorhombie with a : b : c = 0.97756 : 1 : 0.86995, and as having the chemical composition 2PbS.Ag2S.3Sb2S3.
Monazite and Xenotime in European Rocks
Authors: Derby Orville A.
Published: December 2006

As the phosphates of the cerium and yttrium groups, monazite aud xenotime, have proved to be quite widespread microscopic accessories in certain types of Brazilian granites and gneisses, "a batea test has recently been made on a number of hand specimens obtained from the mineral establishment of Dr. F. Krantz, of Bonn, for the purpose of determining if these interesting minerals were equally characteristic of the corresponding types of European rocks. About half of an ordinary museum specimen was crushed in a porcelain mortar to pass through a moderately fine sieve, concentrated in the batea and examined under the microscope after cleaning with the Thoulet or Klein solution, or both, and, when necessary, with the electro-magnet. The identifications of the minerals in the residues thus obtained, especially in cases of doubt, have been kindly revised by Dr. Eugen Hussak.
On a New Occurrence of Apophyllite in South Africa
Authors: Leo Henderson J. A.
Published: December 2006

In the so-called " blue ground " of the tarm Koppiesfontein, in the neighbourhood of Jagersfontein, Orange Free State, a prospecting shaft was put down; and in the 110 ft. level struck a blue-grey, soft, and apparently talcose serpentine-like mass. The latter was densely studded with a great number of small, completely formed, light coloured crystals, which in some places lie very close together. The crystals may be easily isolated from this matrix, in which they leave smooth-sided and sharpedged moulds.
Petrographical Notes on the Rock-specimens collected in Antarctic Regions during the voyage of H.M.S. Erebus and Terror under Sir James Clark Ross, in 1839–43
Authors: Prior G. T.
Published: December 2006

The rock-specimens collected during the Antarctic Expedition of 1839-43 were deposited in the British Museum. A few years ago, in the course of a re-arrangement and registration of the rock-specimens n the Museum, this collection amongst others was examined, and microscopic sections of some of the specimens were prepared. Nothing, however, was published at that time, since it was found that the greater part of the collection had been practically duplicated by the rocks of the Challenger Expedition, which had a year or two previously been deposited in the Museum, and it was felt that mere petrographical descriptions of specimens have but little to recommend them in the absence of geological data as to the mode of occurrence and mutual relations of the rocks in the field.
On some lead minerals from Laurium, namely, Laurionite, Phosgenite, Fiedlerite, and (new species) Paralaurionite
Authors: Herbert Smith G. F. , Prior G. T.
Published: December 2006

In this paper are embodied the results of an examination of the specimens of lead slags from Laurium in the British Museum. On some of the specimens a new mineral, paralaurionite, was found, which possesses the same chemical composition as laurionite, but entirely different morphological and optical characters.

In addition to crystals of the four minerals given in the title, a few crystals oi matloekite and anglesite were noticed, and on one specimen there is a radiating group of prismatic crystals of penfieldite.
On a new mode of occurrence of Ruby in North Carolina
Authors: Judd J. W. , Hidden W. E. , Pratt J. H.
Published: December 2006

Parts of the State of North Carolina, with adjoining areas in South Carolina and Georgia, have long been known to mineralogists and geologists as among the most interesting of corundum localities; and the researches of the late Dr. Genth, Col. Joseph Willcox, Mr. J. Volney Lewis and many other authors have done much to make clear the mode of occurrence and associations of corundum in this area and in the great eorundiferous belt stretching along the line of the Appalachian crystalline area from Alabama in the south to Maine in the north.
On the Crystallography of the Rubies from Macon County, North Carolina
Authors: Pratt J. H.
Published: December 2006

The ruby crystals from the Cowee Valley, Macon County, North Carolina, show a very wide variation in their development. Although many of the crystals are so striated that no crystallographic measurements were possible on the reflecting goniometer, the faces were readily identified by means of the contact goniometer. On some of the crystals the faces were bright and smooth, making them well adapted for measurement on the reflecting goniometer. The following references are to Plate.
Communications from the Oxford Mineralogical Laboratory. On the constitution of the natural Arsenates and Phosphates
Authors: Hartley E. G. J.
Published: December 2006

This mineral, which until now has been regarded as a hydrated arsenate of iron, was mentioned as far back as 1790 by Proust and also by other mineralogists about the same time. In 1801 Chenevix (Phil. Trans. 1801, 220) gave an analysis of an arsenate of iron, but it differs very much in composition from pharmacosiderite in that it contained 9 per cent. of copper. Probably it was not a pure specimen of this mineral. Vauquelin also published an analysis of an iron arsenate which was probably pharmacosiderite (Brongniart, Traité de Min., 1807, II. 182), since he describes it as crystallising in cubes.
On a mass of Meteoric Iron from the neighbourhood of Caperr, Rio Senguerr, Patagonia
Authors: Fletcher L.
Published: December 2006

In the month of September, 1869, Captain Musters, who was st that time making an expedition through Patagonia, had his attention called to a heavy mass of material which he took to be marble. In the account of his journey he afterwards wrote (from memory) as follows:—

"There is in this place, which is called by the Indians Amakaken, a large spherical boulder of marble, which it is the custom of the Indians to try their strength by lifting. Casimiro informed me that this stone had oeen there for many years, and the custom was very old. It was so large and heavy that I was just able to grasp it with both arms and raise it to the level of my knees, but some of the Indians managed to lift it to their shoulders."
Communications from the Oxford Mineralogical Laboratory. On the constitution of the natural Arsenates and Phosphates. Part III. Plumbogummite and Hitchcockite
Authors: Hartley E. G. J.
Published: December 2006

The present paper deals with the somewhat obscure lead aluminium phosphates, of which the following varieties have hitherto been described :—

(i)

The original plumbogummite, a mineral found at Huelgoat in Brittany, and at Nuissière, Dept. Rhône.

(ii)

Some varieties of pyromorphite, containing alumina and water as constituents. These pyromorphites occur also at Huelgoat, and are usually quoted in books on Mineralogy as plumbogummite, although Damour, in his original paper on the subject, clearly distinguishes between the true plumbogummite and the aluminous pyromorphites.

(iii)

The American mineral, bitehcockite, occurring in the Canton Mines, Georgia.

(iv)

A Cumberland mineral, which for some time was mistaken for zinc silicate, but has recently been shown to be a phosphate of lead and aluminium (Miers, Min. Mag. 1896, XI, 272).
Communications from the Oxford Mineralogical Laboratory. Note on the Hitchcockite, Plumbogummite and Beudantite analysed by Mr. Hartley
Authors: Miers H. A.
Published: December 2006

In a description of some British pseudomorphs, published in 1896 (Mineralogical Magazine, XI, p. 272), I mentioned that the sky-blue and lavender-blue mineral sometimes found encrusting the pyromorphite from Roughten Gill is not a zinc carbonate or silicate, as commonly supposed, but is a phosphate of lead and aluminium. Pseudomorphs of this substance after pyromorphite are not rare among Roughten Gill specimens, and these were described in the above mentioned paper as examples of plumboresinite after pyromorphite.
Florencite, a new hydrated Phosphate of Aluminium and the Cerium Earths, from Brazil
Authors: Hussak E. , Prior G. T.
Published: December 2006

Florencite was first discovered as a rare constituent of the cinnabar-bearing sands of Tripuhy, near Ouro Preto, Minas Geraes, Brazil. Here it occurred in well-developed crystals (up to ½ cm. in, length), in association with monazite, xenotime and the titano-anti. monates (lewisite and derbylite) previously described. Blowpipe experiments made hy Dr. W. Florence showed that the mineral was a phosphate of the cerium earths, while angular measurements of the crystals and observations of the optical characters suggested its close relationship with hamlinite, the new hydrated phosphate of aluminium, barium and strontium, recently described by Hidden and Penfield.
Hamlinite, Florencite Plumbogummite (Hitchcockite), Beudantite and Svanbergite, as members of a natural group of minerals
Authors: Prior G. T.
Published: December 2006

In mineralogical literature there appears to be a tendency to overestimate the degree of exactness attainable in the chemical analysis of minerals. When it is considered how impossible in the majority of eases it is to obtain absolutely pure material for analysis, and how imperfect even in these days are some of the methods of chemical separation employed, for the determination of a formula any great reliance in the figures to the right of the decimal point in the percentages obtained is scarcely justified in the case of analyses made on small amounts (less than half a gram) of material.
On Stokesite, a new mineral containing tin, from Cornwall
Authors: Hutchinson A.
Published: December 2006

While engaged last summer in arranging the Carne collection of minerals acquired for the Cambridge Mineralogical Museum in the early part of 1899, my attention was attracted by a single, colourless, transparent crystal, about 10 mm. long, implanted in a shallow cavity on a specimen of crystallised axinite from the St. Just district of Cornwall. In general appearance the crystal resembled somewhat closely one of selenite of the ordinary habit, and indeed was entered as gypsum in the catalogue of the Carne collection.
Petrographical Notes on the Rock-Specimens collected in the Little Island of Trinidad, S. Atlantic, by the Antarctic Expedition of 1839–43, under Sir James Clark Ross
Authors: Prior G. T.
Published: December 2006

The Little Island of Trinidad, as it is called to distinguish it from the larger island in the West Indies, is situated in the South Atlantic Ocean, about 700 miles off the coast of Brazil, in lat. 20°31' S. and long. 29°19' W.

According to Ross, who in 1839 effeeted a landing on tile N.W. coast, the island is a mass of volcanic matter, the rocks of which it is composed assuming the most extraordinary shapes. The most remarkable of these are the Sugar Loaf Hill on the southern and the Nine-Pin Rock on the north-western coast.
On some remarkable composite crystals of copper pyrites from Cornwall
Authors: Lewis W. J. , Hall A. L.
Published: December 2006

During a recent visit to Cornwall the attention of Professor Lewis was directed by Mr. James Wickctt to some composite crystals of copper pyrites recently found in one of the deep mines in the neighbourhood of Redruth. On the specimens acquired by the Cambridge Museum about thirty crystals show this composite growth, which causes the crystals to resemble ill-developed pentagonal dodecahedra of iron pyrites.
On Grassmann's method of axial representation, and its application to the solution of certain crystallographic problems
Authors: Lewis W. J.
Published: December 2006

Grassmann, in his Memoir, Zur physlschen Krystallographie und geometrischen Combinationslehre, published in 1829, referred a crystal to three face-normals--rays--as axes of reference; the parameters being the edges along the axes of a parallelepiped having for diagonal a definite length of a known normal which is not co-planar with any pair of the axial rays. Any other normal is then represented as the diagonal of a similarly formed parallelepiped having for its edges along the axes lengths which are rational multiples of the parameters. Grassmann gave no formulæ for finding in general the indices of face-normals from measurements of the angles on the crystal; nor for determining the angles from the crystal-elements and indices.
On the determination of the positions of points and planes after rotation through a definite angle about a known axis
Authors: Hudson R. W. H. T.
Published: December 2006

Take three axes of reference OX, OY, OZ mutually at right angles. A convention must be made as to the positive direction of rotation about any line, and that usually adopted is as follows. A positive rotation about OX rotates OY towards OZ, one about OY rotates OZ towards OX, and one about OZ rotates OX towards OY. To find the positive direction of rotation for any line ON we must suppose ON moved to coincide with one of the axes, say OZ, and then apply the preceding rule.
Communication from the Oxford Mineralogical Laboratory
Authors: Bowman H. L.
Published: December 2006

The stones to which this paper refers were sent to Prof. Miers for determination by Mr. Francis Powell, and were stated to come " from the diamond washings." They are of a fine green colour, and quite transparent, and possess a highly perfect cleavage parallel to the faces of a prism having an angle of about 88°. This serves to distinguish the material from olivine, which it otherwise much resembles, and --coupled with the uniformly straight extinction through cleavage flakes, the specific gravity (3.199) and hardness (6-7)--suffices to identify the mineral as one of the rhombic pyroxenes.
Conchite, a new Form of Calcium Carbonate
Authors: Kelly Agnes
Published: December 2006

In the course of an investigation on calcareous secretions in the animal kingdom, and more particularly on molluscan shells, I found that the latter did not consist of aragonite, as G. Rose and Sorby had supposed, but of a negative, uniaxial mineral, which is distinguished by most of its properties from calcite, and for which I propose the name conchite (KóγXη, shell). I further found that conehite occurred naturally in many localities--always as a crystal aggregate. Its properties were investigated on such, as well as on the eonchite in shells.
The alteration of Pyrite by underground water
Authors: Evans John W.
Published: December 2006

It has for many years been proposed to form a reservoir with an area of some 36 square kilometres for irrigation purposes near Hiriyur in Northern Mysore, by erecting a dam at Marikanave, where the River Vedavati or Hagari crosses a rocky ridge running north-north-west and south-south-east.

Doubts were raised as to whether the rock would form a sufficiently firm foundation, but Mr. Robert Bruce Foote, late Superintendent of the Geological Survey of India, and my predecessor as State Geologist in Mysore, reported that it was in every way suitable for the purpose.
A List of New Mineral Names
Authors: Spencer L. J.
Published: December 2006

Since the publication, three years ago, of the ficst of these lists at the end of Volume XI of the Minertdogical Magazine, so many new mineral names have been given that a second list may be useful as a completion to Volume XII. In addition to names which have recently been published are a few earlier names which are not to be found in some of the larger works of reference. The numerous compounded chemical and mineral names for artificial substances prepared by Doelter, Lemberg, Thugutt and others, have, with one or two exceptions, been omitted.
On a Question relative to Extinction-angles in rock-slices
Authors: Harker Alfred
Published: December 2006

Many minerals of the rhomhie system are of markedly columnar habit, with the axis of elongation, or vertical axis, as one of the biseetrices of the angles between the optic axes. Such a crystal, in a section parallel to the vertical axis, gives straight extinction. It is natural to expect, and is perhaps generally assumed, that a section slightly oblique to the vertical axis will give nearly straight extinction. The object of the present note is to inquire how far this is true, and in what possible cases a serious error may arise.
A simple proof of the rationality of the anharmonic ratio of four faces of a zone
Authors: Hilton Harold
Published: December 2006

The anharmonic ratio here considered is that of the pencil (P) formed by the four lines (lying in a plane perpendicular to the zonal axis) drawn from any point M perpendicular to four faces of the zone. The anharmonic ratio of the pencil P is evidently independent of the position of M.

Let four planes be drawn through M perpendicular to the four lines of the pencil P; these are parallel to the crystal faces and meet in a line (the line through M perpendicular to the plane of the pencil P and parallel to the zonal axis).

These four planes are cut by the plane of the pencil in a pencil having the same angles, and therefore the same anharmonic ratio, as the pencil P.
Sulpharsenites of lead from the Binnenthal with Plate III
Authors: Solly R. H.
Published: December 2006

Baumhauer, 1896, Zeits. Kryst. Min. XXVI, 598-602. Crystallography. with Analysis by Bömer. (Abstract Min. Mag. XI, 225.)

Jackson, 1900, Min. Mag. XII, 287. Analyses.

System : Rhombic. a : b : c = 0·4782 : 1 : 0·5112.

These ratios are calculated from 010 : 350 = 51°7′ and 010 : 111 = 70°45′ measured On crystal No. 1 (see p. 81). A new orientation has been chosen for the crystals, so that the well-developed prism zone is vertical, and the cleavage plane, (001) of Baumhauer, becomes (010) to correspond with the cleavage of jordanite. The parametral plane has also been changed, chiefly on account of the pyramid planes.
On the remarkable problem presented by the crystalline development of Calaverite
Authors: Herbert Smith G. F. , Prior G. T.
Published: December 2006

The validity of Haüy's great law of the rationality of intercepts — better known as the law of rational indices—or its equivalent, the law of homogeneity of arrangement of the ultimate particles in a crystalline structure, has as yet never been seriously called into question : nevertheless, in the crystals of the telluride of gold, calaverite, we find characters which are to all appearance at variance with this law. As far as the author is aware and can ascertain, no difficulty of a precisely similar kind has ever been encountered before. Certain substances do, indeed, display the so-called optical anomalies; but these are, as was first established by Mallard, in reality in strict accordance with the actual crystalline arrangement.
Sulpharsenites of Lead from the Binnenthal. Part III.—Baumhauerite, a new mineral; and Dufrenoysite
Authors: Solly R. H. , Jackson H.
Published: December 2006

For this new mineral I propose the name baumhauerite in honour of Dr. H. Baumhauer, Professor of Mineralogy in the University of Freiburg, Switzerland, who has done so much to elucidate this complicated group of sulpharsenites of lead.

System: Oblique. a : b : c = 1.136817 : 1 : 0.947168; β = 82° 423/4.

These elements are calculated from the angles 100 : 101=50° 27′ 101:001 = 32° 153/4′ and 010 : 111̄ = 50° 33′ measured on crystal No. I.

The crystals closely resemble dufrenoysite and jordanite in appearance. They may be distinguished from dufrenoysite by the marked oblique development of the zone [100,001], and from jordanite by the absence of twin striations and by the colour of the streak. The edges in the pyramid zone and between planes in the zone [100,010] are more or less rounded.
On Gibbsite from the Palni Hills in Southern India
Authors: Warth H.
Published: December 2006

The mineral described below was found by the present writer, in the year 1893, at Kodikanal on the Palni Hills, in the Madura District of the Madras Presidency. These hills, which rise at Kodikanal to a height of 7000 feet above the sea, form a range some thirty miles long in a WSW.-ENE. direction, with a breadth about half as great. They are composed of grey igneous rock, belonging to Mr. T. H. Holland's ‘Charnockito’ series, the slight foliation being in a direction coincident with that of the range, while the dip is at high angles. The mountains are at present mostly clothed with grass only, the soil being highly Charged with peaty matter, and moderately fertile.
The Cerargyrite Group (holohedral-cubic silver haloids)
Authors: Prior G. T. , Spencer L. J.
Published: December 2006

Historical Introduction.—As given in modern text-books, the holohedral-cubic silver haloids occurring as minerals include the following species: the pure chloride, chlorargyrite, AgCl. ; the pure bromide, bromargyrite, AgBr; the intermediate embolite, Ag(Cl,Br), containing chlorine and bromine in varying proportions ; and iodobromite, containing all three halogens in a definite ratio corresponding to the formula 2AgCl.2AgBr.AgI.

The terms hornsilver (used by Gesner as far back as 1565) and cerargyrite (Beudant, 1832) are usually taken as referring only to the pure chloride. As regards their signification, however, they are equally applicable to all of the above species, and in lack of chemical analyses were certainly so applied in the past. Thus Breithaupt, after the discovery of the bromide and chloro-bromide of silver by Berthier in 1841 and 1842, remarks that many of the specimens of ‘Hornerz’ in the Werner Museum having a greenish colour probably contained bromine.
The Identity of Kilbriekenite with Geocronite : and Analyses of Miersite, Marshite, and Copper-pyrites
Authors: Prior G. T.
Published: December 2006

The mineral kilbrickenite was analysed, described and named by Dr. James Apjohn in 1840. The specimens which he examined were sent to him by Mr. P. M. Taylor, who conducted the mining operations at the Kilbricken mine in County Clare, where the mineral was discovered. Apjohn's analysis showed the presence of lead, antimony and sulphur in proportions corresponding fairly closely with tbe formula 6PbS.Sb2S3. It was only in the preceding year that L. F. Svanberg had described a new mineral, geocronite, to which he assigned the formula 5PbS.(Sb, As)2S3. The announcement of this new mineral appears to have escaped Apjohn's notice, since geocronite is not included in the list of sulphantimonites of lead with which he concludes his paper.
Note on Mica (Fuchsite) as a decorative stone used by the ancients
Authors: Miers H. A.
Published: December 2006

The specimen to which the following note refers was found in the Oxford Collection, and nothing is known of its origin.

It is a polished piece of translucent emerald-green stone, with patches of darker green and also patches of a dull brown colour.

The stone has taken a high polish, and brilliant internal reflections from immediately below the surface of the paler portions give it in those parts almost the appearance of a flawed emerald. But the fractured surface shows it to be merely a massive, pale green, micaceous mineral with brown patches, which appear at first sight to be only an iron-stained variety of the same substance.
Note on the Refrative Indices of Pyromorphite, Mimetite, and Vanadinite
Authors: Bowman H. L.
Published: December 2006

It is somewhat remarkable that a group of minerals, of which such excellent transparent crystals are known as of pyromorphite, mimetite, and vanadinite, should not have hitherto been submitted to a detailed optical examination, except as regards the nature of the interference figures visible in a cross-section. The only reference to the refractive indices of these substances, which I have been able to find, is one by Schroeder van der Kolk, who states that those of pyromorphite amt vanadinite are above 1.93 (as found by immersion in highly refracting liquids), and that they have a birefringence of 0.02 and 0.01 respectively.
Note on rare twins of Calcite from Somerset
Authors: Bowman H. L.
Published: December 2006

The crystals to which this note refers, occur in a quarry in the New Red Sandstone at Bindon, in Somerset, on the property of Mr. H. H. Worthington, and were presented to the Oxford Museum a few months ago by his son, Mr. J. H. Worthington. I have lately had an opportrinity of visiting the locality and examining the mode of occurrence of the specimens.

The crystals have all been obtained from a single, roughly vertical vein in the side of the quarry, which shows an exposure of irregularly alternating beds of red sandstone and conglomerate. The pebbles of the latter consist, for the most part, of a compact purplish limestone, while a few are of greasy-looking quartz.
On some crystals of Quartz from De Aar (Cape Colony) and other localities
Authors: Barker T. V.
Published: December 2006

A Small set of quartz crystals of somewhat peculiar habit, collected by Lieut. E. G. Spencer-Churchill near De Aar, South Africa, and given by him to the Mineral Department of the University Museum, present some features of interest; two crystals, in particular, are remarkable as exhibiting faces seldom observed on quartz. The first has a face X lying in the zone [mz] (or [mr]?), the other a well-developed face in the zone [rz].

The crystal bearing the former face, X, is depicted in fig. 1. As regards habit and other features, it is in all respects similar to the second crystal (fig. 2).

The faces r and z cannot be distinguished with certainty, but cleavage-cracks within the crystal point to the lettering shown in fig. 1. The polariscope proves the presence of both right- and left-handed material.
Sulpharsenites of lead from the Binnenthal. Part IV.—Seligmannite : with a supplementary note on Baumhauerite
Authors: Solly R. H.
Published: December 2006

Professor Baumhauer, in January, 1901, described five very small crystals of a new mineral, to which he gave the name seligmannite. They were associated with rathite and binnite in dolomite, and came from the Lengenbach quarries in the Binnenthal, Switzerland. In June, 1902, he described another crystal, the angles of which agreed fairly well with those of the crystals he had previously measured. In habit and twinning, these orthorhombic crystals so closely resembled bournonite that he ventured to assign to the new mineral the chemical formula Cu2S.2PbS.As2S3, but from paucity of material he was unable to make a chemical analysis.
On the diathermancy of Antimonite
Authors: Hutchinson A.
Published: December 2006

A determination of the constants of elliptic polarization of light reflected from a fresh cleavage surface of antimonite enabled Professor P. Drude to calculate two of the indices of refraction of this substance as 5.17 and 4.49 respectively. Instead, however, of the symmetry-axes of the crystal, regarded as belonging to the orthorhombic system, coinciding with the principal vibration directions in the plane (010), he found that the latter were inclined to the former lines at angles which varied in different observations between 2.6° and 15.4°. These observations, which indicate that the symmetry of antimonite is of the oblique or anorthie type, stand in opposition to those of Professor O. Mügge, who found that exceedingly thin flakes of antimonite placed between crossed nicols in direct sunlight transmitted sufficient light of a deep red colour to enable him to determine the extinction as straight.