Sapphires are among the most precious gems, yet they consist solely of chemically 'contaminated' aluminum oxide, or corundum. It is widely assumed that these crystals with their characteristically ...

Glittering blue sapphires, so suggestive of piercing cold, have remarkably hot origins deep beneath the surface. For years, sapphires been turned up in volcanic deposits such as the Volcanic Eifel, ...

A sapphire from sediment in the Kyll, a river in the western Eifel. The crystal measures approximately 0.9 mm in diameter. Sapphires are among the most precious gems, yet they consist solely of ...