Cassiterite

Real mineral · uncommon · SnO₂

Tin oxide and the primary ore of tin. Forms in granitic pegmatites and high-temperature hydrothermal veins. Its exceptional density causes it to concentrate in alluvial placer deposits where it has been mined since the Bronze Age.

Identity

Formula

SnO₂

Chemical class

oxide

Mineral group

Pyrolusite, Rutile

Also known as

Tin stone, Stream tin

Crystallography

Crystal system

tetragonal

Habits

prismatic, massive, nodular

Fracture

subconchoidal

Physical properties

Mohs hardness

6.5

Density

7.01 g/cm³

Luster

adamantine, metallic

Colors

black, brown, reddish brown, yellow, colorless

Streak

white to pale brown

Transparency

transparent, translucent, opaque

Geology

Origins

igneous, hydrothermal

Host rocks

granite, pegmatite, quartz veins

Associated minerals

Quartz, Tourmaline, Wolframite, Arsenopyrite

Geography

China, Indonesia, Bolivia, Myanmar, Brazil

Classification

Rarity

uncommon

Gem quality

No

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