Star of India
Part of Allison and Roberto Mignone Halls of Gems and Minerals.
Denis Finnin/© AMNH
The spectacular Star of India is just over 563 carats, making it the largest gem-quality star sapphire known. It is celebrated for its well-defined star, which is technically a flaw created by trace amounts of the mineral rutile. As the old saying goes, there’s beauty in imperfection.
This gem is also about 2 billion years old. It formed roughly when photosynthesis—the process by which organisms use sunlight, carbon dioxide, and water to produce sugar and oxygen—began on Earth!
Sapphire is a gem variety of the mineral corundum. Beyond the classic blue color, sapphires range from colorless to orange to green to violet, but not red—red corundum is ruby.
