Cassiterite
Image: Robert M. Lavinsky (CC BY-SA 3.0)
Mineral NameCassiterite
Chemical FormulaSnO2
Mohs Hardness6.5
Crystal Systemtetragonal
Lusteradamantine
Streak Colorwhite to brownish-white
Cleavagepoor on {110} and {100}
Fractureconchoidal
Specific Gravity7
Colorsbrown, black, reddish-brown, yellowish-brown, gray
Transparencyopaque to translucent
Type LocalityShengus (Shingus), Haramosh Mts., Skardu District, Baltistan
Mineral GroupOxides
Usestin ore, collector
Associated Mineralsberyl, quartz, feldspar, tourmaline, topaz
Rarityuncommon
Description
This specimen features dark brown to black, well-formed, prismatic to blocky crystals of cassiterite, exhibiting a distinct adamantine luster, associated with lighter-colored beryl crystals.
Geological Context
Cassiterite is the primary ore of tin, typically forming in high-temperature hydrothermal veins, pegmatites, and greisens associated with granitic intrusions. It is also found in placer deposits due to its high specific gravity and resistance to weathering.
