2 : SULFIDES and SULFOSALTS (sulfides, selenides,
tellurides; arsenides, antimonides, bismuthides; sulfarsenites,
sulfantimonites, sulfbismuthites, etc.) D : Metal Sulfides, M: S = 3 :4 and 2:3
C : Variable M:S
Tsumoite
is a member of the Ingodite Group of minerals and contains
only Bismuth and
Tellurium
with the chemical formula BiTe. It is a rare Bismuth Telluride
mineral which is opaque, silver-white in color with
a metallic luster. It is often found as
tiny rounded hexagonal plates, from 1 to 5 mm, and as irregular
aggregates often associated with Gold and Tellurobismuthite
in a white Quartz matrix.
The picture above shows tiny Tsumoite and Gold
crystals in Quartz. If you hover your cursor over the
picture it will show a magnified view of the silvery
Tsumoite crystals and bright yellow Gold crystals and
possible lead-gray Tellurobismuthite crystals on white
Quartz. This
rare gem comes from the Björkdal Mine, Sandfors, Västerbotten, Sweden.
Tsumoite
is named after its discovery locality, the Tsumo Mine, Shimane Prefecture, Japan. The
Tsumo Mine is located about 50 km northwest of Hiroshima
City. The area comprises Paleozoic sedimentary rocks,
their metamorphic equivalents, and acidic igneous rocks
of late Cretaceous age. Although Tsumoite was
discovered in 1972, it was not published
until an article by Hidehiko Shimazaki and Tohru
Ozawa in the 1978, volume 63, issue of American Mineralogist
(1162–1165). The IMA also
approved Tsumoite as a new mineral species in 1978.
Tsumoite
distribution: from Japan, in the Tsumo mine,
about 50 km northwest of Hiroshima City, Shimane Prefecture
[Type Locality]. At the Dashuigou Tellurium deposit,
Sichuan Province, China. In the Ban Phuc deposit, northwestern
Vietnam. From the Kolar Gold Fields, Karnataka, India.
In Russia, at the Tyrnyauz W–Mo deposit, left bank of
the Baksan River Valley, northern Caucasus Mountains;
in the Alekseevskoye mine, Sutam district, Stanovoi
Range, southeast Sakha. From the Ransko massif, about
18 km east-northeast of Havličkův Brod, Czech Republic.
At Úhorná, Slovakia. From the Bjorkdal
gold mine, Vasterbotten, and at Tunaberg, Sweden. From
Sylvanite, Hidalgo County, New Mexico, USA. In the Copper
Cliff South mine, Sudbury, Ontario, Canada. A few additional
poorly located localities are known.
Tsumoite
gems for sale:
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