Trogtalite is a rare selenide mineral with the formula Co Se_2. It crystallizes in the cubic system and is part of the

pyrite The mineral pyrite ( ), or iron pyrite, also known as fool's gold, is an iron sulfide with the chemical formula Fe S2 (iron (II) disulfide). Pyrite is the most abundant sulfide mineral. Pyrite's metallic luster and pale brass-yellow hue ...

group, consisting of Co²⁺ and Se₂²⁻ ions. It has a rose-violet colour and its crystals are opaque. It often occurs as grains. It was thought to be dimorphous with hastite, but this was discredited in 2009. Hastite turned out to be the iron selenide mineral

ferroselite Orthorhombic ferroselite and its isometric polymorph dzharkenite are iron selenides of general formula FeSe2 precipitated under reducing conditions in anoxic environments. They are a source of selenium in the Rocky Mountains where selenium occu ...

. It forms a solid solution series with kruťaite.

Occurrence

Trogtalite was first found in 1955 in Trogtal quarry, Lautenthal,

Harz Mountains The Harz (), also called the Harz Mountains, is a Mittelgebirge, highland area in northern Germany. It has the highest elevations for that region, and its rugged terrain extends across parts of Lower Saxony, Saxony-Anhalt, and Thuringia. The nam ...

, Germany, after which it was also named. It often occurs intergrown with

clausthalite Clausthalite is a lead selenide mineral, PbSe. It forms a solid solution series with galena PbS. Occurrence It occurs in low-sulfur hydrothermal deposits with other selenides and in mercury deposits. It is associated with tiemannite, klockmann ...

grains at this locality. It has also been found in the Musonoi Cu–Co mine, Kolwezi,

Katanga Province Katanga was one of the four large provinces created in the Belgian Congo in 1914. It was one of the eleven provinces of the Democratic Republic of the Congo between 1966 and 2015, when it was split into the Tanganyika Province, Tanganyika, Hau ...

, Congo and in Argentina, in Tuminico, Sierra de Cacho, and in Los Llantenes, La Rioja Province. It is often found together with clausthalite,

, bornhardtite, native selenium,

gold Gold is a chemical element; it has chemical symbol Au (from Latin ) and atomic number 79. In its pure form, it is a brightness, bright, slightly orange-yellow, dense, soft, malleable, and ductile metal. Chemically, gold is a transition metal ...

, and

oosterboschite Oosterboschite is a rare selenide mineral with the formula . It crystallises in the orthorhombic crystal system. It has a creamy yellow colour and a Moh's hardness of 5. It is often found as grains with no clear shape. The crystals are opaque and ...

References

{{reflist Selenide minerals Cobalt minerals Cubic minerals Minerals in space group 205

Occurrence

See also

References