Arizona weekly citizen., 1889-06-01
Iron Pyrites, or Fools Gold.

> Iron Pyrites, or Fools Gold It is common experience with chem l ists to have brought to them for exami nation, package containing some crys
 tals of yellow color, which the finder confidently believes to be gold. The
 story of the man who brought sample
 to Dr. Jackson for examination, after he had married the widow "who owned a
 whole hill of it," instead of before, is
 well known, and his unfortunate ex
 perience serves to illustrate the old pro
 verb that "all is not gold ithat glitters'
 Iron pyrites pronounced, according to
 the best authorities, pi-rites) is common
 everywhere, and sometimss-but not
 often-really does contain a trace of
 gold, although usually it is entirely
 worthless.
 It is, chemically considered, dis
 ulphide of iron, Fe S2, containing, when
 pure, 46,7 per cent. iron and 53.3 per cent
 sulphur. Unlike gold, it is one of the
 most abundant substances, being found in nearly every geological formation, and
 in every part of the world. It has pro
 bably been formed from sulphate of iron
 by the action of organic. matter, which
 has removed all the oxygen, or, in other
 words, reduced it to a sulphide. It is
 very hard, being but little inferior to quartz in this respect, and will strike fire with steel, like flint; hence the name of pyrite-fire stone. In this respect it is quite unlike native gold, which is very soft. Its lustre is brilliant and metallic. In color it varies somewhat sometimes it is pale yellow and closely resembles brass, at other times it has the color of gold, and sometimes it is brown or gray. In fine powder it is brownish black, and leaves black streak on rough
 porcelain or honestone,
 Pyrites are generally foundIcrystallized
 gold, very rarely. Large and fine crys-
 tals of pyrites have been found in Colo
 rado and on the Isle of Elba. In lime
 stone and states, small crystals are fre-
 quently met with. The crystals are
 usually cubes, which are frequently stir ated in peculiar manner, so that the lines of any two adjacent faces are never parallel. A very characteristic form of crystal. although much rarer than the cube, is one bounded by twelve penta- gonal faces, with or without three small Ter faces on eight of the corners. An other very interesting form of crystal is bounded by twenty triangular faces. This last is the result of combining a | dodecahedron with an occahedran. It | also forms twin crystals one of which l IS known as the iron-cross, and looks as thhoug one cube had been pushed into and through the other one.
 The principal use of the iron pyrites | is in the manufacture of sulphuric acid, | but in England sulphur is also made | from it. It frequently contains arsenic, | which then passes into the acid made | from it. Sometimes it contains selen- | ium, which is then found in the slime on | the floor of the leaden chambers. As | an ore of iron it is practically useless, owing to the great difficulty of remov- ing the last traces of sulphur and other | injurious substances Slaty clay, which | contains much pyrites, is used for mak- alum, for, by simply roasting and ex- posing to the air in a moist state, sul- Il phates of aluminium and iron ore form ed, which need only the addition of an alkaline chloride, such as ammonium or potassium, to convert it into alum and | remove the iron.
 Pyrites sometimes contains gold, and | those found in gold-bearing districts | should always be tested for the precious metal. There IS no characteristic by | which gold bearing pyrites are readily | distinguished from the ordinary sort, and when there is sufficient reasons to suspect the presence of gold, the ore should be suou1irteS Sto 2 competent as- sayer for examinatiohs since a paying quantity of gold could easily escape de lection by a less experienced person. The reduction of the gold in the pyrites is attended with many difficulties, but they are daily being overcome in prac- tice.
 Before closing we would mention the fact that there are several kinds of pyrites besides iron pyrites. There is also another disulphide of iron, with the same composition as the one described, but lighter in color, called marcasite. It crystallizes in the trimetric system but also occurs in globular, reniform, and other initiative shapes resembling petrified fruit, and massive. It is much less common than the cubical or yellow pyrites.
 Glance-cobal contains arsenic and cobalt, as we'll as iron and sulphur. In crystalline form 1t is very like the iron pyrites, but in color lighter, with faint shade of pink. It is quite rare, being found chiefly in Sweden,
 Mispickel also called arsenical pyrites, is of steel-gray color, very hard and in the same form of mar castle, it contains about 40 per cent of arsnic. It is found in Sweden, the Hartz mountains, and this country.
 Copper pyrites is a compound of sul- phur with iron and copper, It is much softer and of darker color than iron pyrites, and often exhibits rainbow tints. Good crystals are not common, and the | surface is usually irregular or conchoi- dal. 1t is valuable ore of copper.
 All kinds of pyrites are attacked by strong nitric acid, with the evolution of red fumes; gold is not. The odor of burning sulphur and sometimes of ar senic, when strongly cheated, and also pyrites from the precious