The Black Prince’s Ruby. The Timur Ruby. For centuries, spinel, the great imposter, masqueraded as ruby in Europe’s crown jewels.

• Mineral:   spinel
• Chemistry: MgAl2O4
• Color: red, orange, pink, purple, blue, black
• Refractive index: 1.718
• Birefringence: none
• Specific gravity: 3.60
• Mohs Hardness: 8