MlNERALOGlC TERMINOLOGY AND DESCRIPTIONS 

A UTHORS WHO PLAN TO REPORT on the squares algorithm is standard practice. Questions 

optical, physical, crystallographic, or chemical regarding choice of crystallographic axes, standard 

properties of either existing minerals or proposed new settings, and other recognized conventions of crystalminerals should review the guidelines below. lography are addressed by the "International Tables 

for X-Ray Crystallography" (International Union of 

MINERAL NAMES Crystallography, 1952, 1959, 1962, 1974, 1983). 

Conditions under which X-ray diffractometer data 

A complete compilation of mineral names, are collected should be described. For manual systems 

periodically updated and corrected, is given by this description should include the data-collection 

Fleischer (1983), including errata. Fleischer's glossary speed in degrees 28 per minute, 28 range, slit conprovides correct spelling and chemical formulas for figuration, time constant, and generator power setmore than 2,900 mineral species in a convenient tings. For automated systems or manual systems 

alphabetical format. utilizing stepping motors, the slew speed is replaced 

by values for step size and step time. The use of a Authors Ehuld avoid colloquial l-Em-les (sunstone), theta slit should always be if 

outdated names (plumbago instead of graphite), no intensity corrections are made for its presence. nonspecific mineral terms (sericite, psilomelane, Any algorithms used to locate or fit diffraction peaks asbestos), and varietal names without reference to the should also be reported. parent mineral species (kunzite without reference to 

spodumene). 

Correct standard terminology for morphological, 

physical, and optical properties of minerals may be 

verified in standard references such as Klein and 

Hurlbut (1985). Widely accepted abbreviations for 

physical quantities are given on the inside back cover 

of each issue of the journal "American Mineralogist." 

Some of these abbreviations are not included in the 

STA listing of abbreviations in table 4, page 109; 

some also differ slightly from those listed. 

Acceptable abbreviations for reporting X-ray 

diffraction data are also given by the "American 

Mineralogist." The use of nanometers (nm) rather 

than angstroms (A) is now preferable (see "The 

Metric System," p. 122, for USGS policy). 

Guidelines for the publication of X-ray powder data 

are given by Bayliss (1976). The use of single-crystal, 

powder diffraction, or Guinier film techniques is recommended over Debye-Schemer or Gandolfi methods 

in the interest of unique indexing, more reliable intensity data, or better resolution, respectively. Correction of lines to an internal standard is desirable, and 

refinement of cell parameters by a suitable leastGeneral aspects of chemical nomenclature are 

described in the preceding section entitled "Chemical 

Terminology." Some special consideration is needed, 

however, when reporting minerals whose substitutional chemistry leads an author to propose a prefix, 

suffix, or adjectival modifier to indicate the nature of 

the substitution. Authors should be aware that the 

use of any prefix or suffix with an existing mineral 

name is considered to be a new name by the International Mineralogical Association (IMA) and that only 

adjectival modifiers can be used without creating a 

new mineral name. The distinctions between these 

three types of modifiers, and when their use is appropriate, are outlined in Hey and Gottardi (1980). 

The salient points of these usages are summarized 

below. 

To indicate a family name ("mica") 

To indicate a dominant end-member species 

("siderite") 

To indicate a variety of a mineral species ("kunzite") 

Mineralogic terminology and descriptions 93 
To indicate crystallographic information 

("clinoenstatite") 

No unique implication ("parachrysotile") 

To indicate chemistry ("ferroglaucophane") 

Prefixes may be joined with the mineral name or 

separated by a hyphen. Chemical prefixes should be 

used only when the element named is dominant in an 

isomorphous series and the author wishes to introduce 

a new name. (This usage constitutes a new mineral 

name and is subject to approval by the IMA.) 

A mineral name also may be suffixed. A suffix, as 

used here, is a symbol, a chemical or crystallographic 

one, that follows a mineral name and is attached to it 

with a hyphen. The suffiix gives some particular additional information; for example "monazite-(La)," 

which means a monazite in which La is dominant 

among the rare earth elements; another example is 

"graphite-BH," which names a special polytype 

of graphite (Hey and Gottardi, 1980). 

The use of a suffii also creates a new mineral name 

and is subject to approval by the IMA. Use of a chemical suffix for rare earth minerals is now standard, 

and in the format just shown (Levinson, 1966). 

Adjectival modifiers are used to denote nondominant chemical substitution in an isomorphous series. 

Their use does not create a new mineral name and 

therefore does not require IMA approval. Proper 

usage combines the adjectival form of an element 

name (separate word) immediately followed by a 

mineral name-for example, "ferroan glaucophane." 

Under this rule a clear distinction is made between 

terms like "ferroglaucophane," which indicates 

Fe>Mg and is a mineral name proper, and "ferroan 

glaucophane," which indicates Fe<Mg and is merely a 

mineral name with an adjectival modifier. 

Avoid the use of nouns as adjectival modifiers 

because of possible misunderstanding of intent. For 

example, the modifier "manganese" in "manganese 

tremolite" may imply either a manganese-rich 

tremolite or the manganese equivalent of tremolite. 

Element names should therefore be converted to the 

adjectival form when they are used as modifiers. 

For minerals that can accommodate many substitutions (for example, the amphiboles and pyroxenes), 

the use of adjectival modifiers, prefixes, and suffixes 

can be more confusing than enlightening. Attempts to 

systematize the nomenclature are given in several 

short-course volumes of the Mineralogical Society of 

America (Prewitt, 1980; Veblen, 1981; Bailey, 1984). 

A similar systematization for phyllosilicates is given 

by Bailey (1980). If no previous nomenclature exists 

and prefixes, suffixes, or modifiers would only cause 

confusion, the author should simply use explicit 

chemical formulas whenever possible. 

Before reporting a new mineral species, the author 

should thoroughly investigate the possibility of a 

previously published description. The outline of Donnay and Fleischer (1970) is recommended to authors 

describing new minerals. All proposed new mineral 

names must be approved by the Commission on New 

Minerals and Mineral Names of the International 

Mineralogical Association. Approval is needed before 

the manuscript is published and should be noted on 

the first page of the manuscript as a footnote immediately after the new mineral name in the title. 

When naming new minerals, authors should consider 

possible similarities to already existing mineral names 

and should consider possible confusion resulting from 

non-English pronunciation. In naming new rare-earth 

minerals, the applicable rules should be followed 

(Levinson, 1966). 

94 Mineralogic terminology and descriptions