Naturalsulphides

Pyrite               Molibdenite
Cellular pyrite   Galena
Chalcopyrite     Sphalerite

These combinations of elements are mainly metals with sulfur. Sulphides aren’t rock-formative, but they are of practical interest as the ores of ferrous and non-ferrous metals. Specific features for minerals of this class is metallic shine (except sphalerite) and dark line. Sulphides are not transparent. Let’s consider one of them.

Pyrite – is grey or iron firestone. Golden-yellow or straw-yellow colour in the piece, almost black, with a slight greenish tint in the form of powder. Shine is intense, metallic, not transparent. Break is uneven, shell-like, cleft is not complete, hardness in 6-6,5, unitfair weight is hard. It occurs in the form of granular or pan mass, rounded nodules radical-radiant structure, as well as in the form of well-marked crystals, cubic shape with a thin parallel shading at the edges.

It differs with bright-golden colour, high hardness and form of crystals with the shading at the edges. The origin of contact-metamorphic, hydrothermal less formed by decomposition on the remains of animals and plants in sedimentary rocks.

According to chemical composition cellular pyrite is similar to pyrite. But unlike pyrite cellular pyrite has another crystalline structure and occurs in the form of real-radiant attachment or coupe like crystals and pectinal doubles. Cellular pyrite has a greenish tint on the break, which is not typical for pyrite.

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