The Cassiterite is a mineral that results from oxidation of tin (SnO 2) is a typical mineral pegamtitas , ie is associated with late stage of granite crystallization ( neumatolisis ). In granites and pegmatites neumatolíticos, cassiterite is usually accompanied by wolframite, sheelita and mispíquel .
The cassiterite typically contains 87% tin and 21% of oxygen (plus iron , tantalum and other minerals ) is durísma, heavy and fragile, impervious to acids. Appears in crystals thick, prismatic, often in twin tetragonal system belonging to (with variants ditetragonales and dipiramidales). Less known is often the acicular tin , ie, fine crystals in the form of needle, or in a tin woody , similar to wood. Instead, it is unusual to see him as a loose globular granules ( pleasure tin).
- Hardness between 6 and 7 points on the Mohs Scale Exfoliation
- imperfecta. Specific Gravity
- between 6.8 and 7.1 Kg/dm3
- Color brown almost black (colophony less frequent in yellow, gray or red hyacinth
- System: Tetragonal
- Formula: SnO 2
- Hardness: 7
- Source: pegmatite, hydrothermal and secondary in river or marine pleasure.
- Sites: Germany, Czechoslovakia, France, USSR, Cornwall (Great Britain).
- Applications: As tin ore
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