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There are very few tin minerals and cassiterite is the best known. Gemstones fashioned from cassiterite are quite striking. This is due in good part to its high dispersion, which is nearly double that of diamond. It is especially prized by gemologists and mineralogists for its unusual twinned crystal formations. Durable and dense, it has been used as the chief ore of tin from early history throughout the ages, and remains so even today. Many of the economical Cassiterite deposits exist in placer stream deposits where this very heavy mineral collects as rounded water worn pebbles. The name Cassiterite is derived from the Greek "kassiteros", meaning tin.

Cassiterite Rough
Cassiterite Classification
Common Name Cassiterite
Species Cassiterite
Cassiterite Optical Properties
Transparency Transparent - Opaque
Dispersion Strength: Strong Fire Value: 0.071
Refractive Index Over The Limit 1.997-2.098
Birefringence 0.096-0.098
Optic Character Uniaxial
Optic Sign Positive
Polariscope Reaction Doubly Refractive (DR)
Fluorescence SWUV: Inert
LWUV: Inert
Pleochroism Trichroic, weak to moderate greenish yellow, brown, reddish brown
Cassiterite Characteristic Physical Properties
Hardness 6-7
Streak White To Light Yellow
Specific Gravity 6.870-7.030 Typical:6.950
Toughness Varies
Inclusions Cassiterite is typically color zoned and has strong doubling and fire.
Luster SubAdamantine, Adamantine
Fracture Conchoidal, Uneven
Cleavage Good, in one direction
Cassiterite Chemistry & Crystallography
Chemical Formula SnO2
Crystal System Tetragonal
Chemistry Classification Oxide

Cassiterite Colors

  • Colorless Cassiterite Colorless
  • Brown Cassiterite Brown
  • Black Cassiterite Black
  • Yellow Cassiterite Yellow
  • Gray Cassiterite Gray
  • White Cassiterite White

Alternate Names

Tin Stone, Tin Ore, Wood Tin, Toad's Eye Tin

Countries of Origin

China; Namibia; Brazil; Australia

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Tim Matthews


Tim Matthews

Tim Matthews is President and Chief Executive Officer of Jewelry Television® (JTV), as well as a member of the company's Board of Directors. He oversees and leads all aspects of the company's powerful omni-digital retail platform that uniquely specializes in fine jewelry and gemstones. His passion for business and gemstones has led him to become a recognized expert in the field of gemology. He is a life member of the Gemmological Association of Great Britain (Gem-A) and has earned Gem-A's highest degrees, the Gemmology (FGA) and Diamond (DGA) diplomas. He is also a Graduate Gemologist (GG) of the Gemological Institute of America (GIA) and has also completed GIA's Graduate Diplomas in Diamonds, Colored Stones and Pearls. Under his leadership, JTV has become the leader in the sourcing and selling of color gemstones and jewelry.

This page was created on June 27, 2014.

This page was last edited on October 24, 2019.