Cassiterite

Tin dioxide, the main ore of tin — heavy, shiny brown-black crystals.

Cassiterite specimen — Photo: CarlesMillan, CC BY-SA 3.0, via Wikimedia Commons

How to identify cassiterite

Very heavy for a non-metallic mineral.
Brown to black with a brilliant luster.
Light-colored streak despite the dark color.

Often confused with

Wolframite
Wolframite has a perfect cleavage and darker streak.
Compare side by side
Rutile
Rutile is lighter and more striated.
Compare side by side

Where it's found

Cornwall, England
Llallagua, Bolivia
Bangka, Indonesia
Yunnan, China

Uses

Tin for solder, tin plate and bronze.

Rock tumbling

Can be tumbled with care.

Did you know?

Cornish tin was traded across Europe in the Bronze Age, when tin was essential for making bronze.

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