Antimony
Antimony is another hard, brittle metal, of bluish-white color. Exposed to the air at ordinary temperatures it does not tarnish; and this combined with its hardness make it useful for such alloys as Britannia metal, type metal, and pewter. Only one of its minerals, stibnite, is common enough for mention.
[Stibnite]
Sb₂S₃
[Pl. 25]
gray antimony
Occurs in prismatic or needle-like crystals; hardness 2; specific gravity 4.5; color lead-gray; streak lead-gray; luster metallic; opaque.
The crystals of stibnite are orthorhombic and usually elongated, the sides striated and the ends with low pyramids on them. Sometimes the long crystals are curved or even twisted. There is a well-developed cleavage parallel to face b in the figure. While the color is similar to that of galena, the form and cleavage are so different that stibnite is easily determined.
The ancients used stibnite to color their eyebrows, now it is the source for the metal antimony. Hungary and Japan are famous for the fine large crystals they produce; but moderate sized crystals may be found in this country. It occurs in veins along with pyrite, galena, cinnabar, and realgar, with quartz, calcite or barite as gangue minerals.
Stibnite has been found in Arkansas, California, Nevada, and Utah.