Drysdallite
Encyclopedia
Drysdallite is a rare molybdenum
selenium
sulfide mineral
with formula Mo(Se,S)2. It crystallizes in the hexagonal system as small pyramidal crystals or in cleavable masses. It is an opaque metallic mineral with a Mohs hardness of 1 to 1.5 and a specific gravity
of 6.25. Like molybdenite
it is pliable with perfect cleavage.
It was first described in 1973 for an occurrence in an oxidized uranium deposit near Solwezi
, Zambia
. It was named for A.R. Drysdall, the director of the Zambian geological survey.
Molybdenum
Molybdenum , is a Group 6 chemical element with the symbol Mo and atomic number 42. The name is from Neo-Latin Molybdaenum, from Ancient Greek , meaning lead, itself proposed as a loanword from Anatolian Luvian and Lydian languages, since its ores were confused with lead ores...
selenium
Selenium
Selenium is a chemical element with atomic number 34, chemical symbol Se, and an atomic mass of 78.96. It is a nonmetal, whose properties are intermediate between those of adjacent chalcogen elements sulfur and tellurium...
sulfide mineral
Sulfide mineral
The sulfide minerals are a class of minerals containing sulfide as the major anion. Some sulfide minerals are economically important as metal ores. The sulfide class also includes the selenides, the tellurides, the arsenides, the antimonides, the bismuthinides, the sulfarsenides and the sulfosalts...
with formula Mo(Se,S)2. It crystallizes in the hexagonal system as small pyramidal crystals or in cleavable masses. It is an opaque metallic mineral with a Mohs hardness of 1 to 1.5 and a specific gravity
Specific gravity
Specific gravity is the ratio of the density of a substance to the density of a reference substance. Apparent specific gravity is the ratio of the weight of a volume of the substance to the weight of an equal volume of the reference substance. The reference substance is nearly always water for...
of 6.25. Like molybdenite
Molybdenite
Molybdenite is a mineral of molybdenum disulfide, MoS2. Similar in appearance and feel to graphite, molybdenite has a lubricating effect that is a consequence of its layered structure. The atomic structure consists of a sheet of molybdenum atoms sandwiched between sheets of sulfur atoms...
it is pliable with perfect cleavage.
It was first described in 1973 for an occurrence in an oxidized uranium deposit near Solwezi
Solwezi
Solwezi is the capital of the North Western Province of Zambia. Solwezi has approximately 65,000 inhabitants at an elevation of 1235 m above sea level...
, Zambia
Zambia
Zambia , officially the Republic of Zambia, is a landlocked country in Southern Africa. The neighbouring countries are the Democratic Republic of the Congo to the north, Tanzania to the north-east, Malawi to the east, Mozambique, Zimbabwe, Botswana and Namibia to the south, and Angola to the west....
. It was named for A.R. Drysdall, the director of the Zambian geological survey.