Category
page 1Minerals described in 1889

sperrylite
thumb|Sperrylite on chalcopyrite with [[magnetite, Oktyabersky Mine, Norilsk. Field of view 2.2 cm.]]
Sperrylite is a platinum arsenide mineral with the chemical formula and is an opaque metallic tin white mineral which crystallizes in the isometric system with the pyrite group structure. It forms cubic, octahedral or pyritohedral crystals in addition to massive and reniform habits. It has a Mohs hardness of 6–7 and a very high specific gravity of 10.6.
antlerite
Antlerite is a greenish hydrous copper sulfate mineral, with the formula Cu3(SO4)(OH)4. It occurs in tabular, acicular, or fibrous crystals with a vitreous luster. Originally believed to be a rare mineral, antlerite was found to be the primary ore of the oxidised zones in several copper mines across the world, including the Chuquicamata mine in Chile, and the Antler mine in Arizona, US from which it takes its name. It is chemically and optically similar in many respects to other copper minerals such as malachite and brochantite, though it can be distinguished from the former by a lack of effer
tamarugite
Tamarugite (NaAl(SO4)2·6H2O) is a colorless monoclinic sulfate mineral.