Star sapphire, Star of Lanka

Royal Ontario Museum

Royal Ontario Museum

Scientific Name: Corundum
Variety: Star sapphire
Object Type: Gem
Chemistry Formula: Al2O3
Chemistry Type: Hematite group
Image Number: ROM2004_929_8

A pure sapphire is colourless. It is the inclusions within the mineral’s or gem’s structure that impart colour. Inclusions of tiny atoms of iron and titanium create the colour of blue sapphire. The asterism effect of this gem is also remarkable; the star is formed from rutile mineral inclusions that when polished, reflect bands of light back up to the eye.

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  • Title: Star sapphire, Star of Lanka
  • Location: Sri Lanka (Ceylon)
  • Physical Dimensions: 30mm x 27mm x 23mm; 193 carats, high cabochon cut
  • Type: Gem
  • Accession Number: M22286