Images
Formula: IrSbS
Sulphide, cobaltite group,
iridium- and antimony- bearing
mineral
Crystal system: Isometric
Specific gravity: 10.50 calculated
Hardness: 7½
Streak: Steel-grey
Colour: Grey under reflected light
Magnetism: Not magnetic
Common impurities: Pt,Os,Ni
Environments
Localities
At the type locality, the Tolovka River placer, Ust'-Bel'skii ultrabasic Massif, Koryak Okrug, Kamchatka Krai,
Russia, tolovkite occurs as intergrowths included in
osmium-iridium alloys which come
from placer deposits associated with an Alpine-type gabbro massif in
the basin of the Tolovka river. The inclusions are anhedral (18 x 18 microns) and also form aggregates with a
skeletal isometric crystalline outline (up to 50 x 72 microns). The grains are corroded on the surface and associated
with laurite, pentlandite,
heazlewoodite and
native osmium. Under the binocular, particles of tolovkite have a
steel-grey colour, metallic lustre, conchoidal fracture, and are non-magnetic. Under reflected light
tolovkite is grey, distinctly paler than laurite but with a very pale
brown tint
(AM 67.1076-1077, HOM, Mindat).
Tolovkite from the Tolovka River placer -
Image
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