Characteristics of Cassiterite:

Chemical Name: Tin oxide

Formula: SnO2

Colors: Medium to dark brown

Structure: Tetragonal

Hardness: 6-7

Specific Gravity: 6.7-7.1

Refractive Index: 2.0-2.1

Lustre: Adamantine to metallic

Streak: White, greyish, brownish

Locations: Portugal, Italy, France, Czech Republic, Brazil, Myanmar

What is  Cassiterite?

Cassiterite, a major source of tin, takes its name from Kassiteros, the Greek word for the element. The vast majority of cassiterite is opaque black or brown, but occasionally transparent, reddish-brown crystals are found and can be faceted for collectors. Facet-grade crystals are sometimes recovered from rock, but most gemstone material is collected from stream gravels where it has weathered from the rocks in which it formed. Cassiterite continues to be mined for tin, especially in Malaysia, Thailand, Indonesia and Bolivia.