Browse all objects from the National Gem Collection currently viewable online. Sort by mineral, collection, country, or setting.
Photograph of a group of sapphires from the National Gem Collection showing color variation
Photo by Chip Clark
CorundumRubies and sapphires are varieties the same mineral: corundum. Pure corundum, composed of aluminum and oxygen atoms, is colorless. Color variations come from light interacting with impurities that replaced atoms of aluminum in the growing crystals.
Hover over color tiles above to learn what this object tells us about the history of the Earth
|G2172||Corundum (var. Sapphire)||Burma||16.80 ct||More info »|
|G3106||Corundum (var. Sapphire)||Sri Lanka||15.20 ct||More info »|
|G3549||Corundum (var. Sapphire)||Upper Burma||92.60 ct||More info »|
|G3581||Corundum (var. Sapphire)||Sri Lanka||15.73 ct||More info »|
|G3875||Corundum (var. Sapphire)||Sri Lanka||22.40 ct||More info »|
|G4357||Corundum (var. Sapphire)||Sri Lanka||31.06 ct||More info »|
|G4370||Corundum (var. Sapphire)||Sri Lanka||27.42 ct||More info »|
|G4371||Corundum (var. Sapphire)||Sri Lanka||42.20 ct||More info »|
|G4372||Corundum (var. Sapphire)||Sri Lanka||19.90 ct||More info »|
|G9808||Corundum (var. Sapphire)||Unknown Locality||10.28 ct||More info »|
About this object
Sapphire is a gem variety of the mineral corundum. Pure corundum is colorless, but small amounts of impurities in the crystal structure can produce a range of vivid colors. A few atoms of chromium tint corundum the deep red color of ruby, the most prized corundum gem. Iron and titanium, on the other hand, are responsible for the deep blue color of sapphire. Other impurity atoms can color corundum crystals a range of hues, from pink, yellow, and orange to purple, green, and even black. Corundum gems other than red or blue are called fancy colored sapphires. The fancy colored sapphires pictured here range in size from 10.3 to 92.6 carats. The green and large yellow sapphires are from Burma; the others are from Sri Lanka.
denotes specimens currently on exhibit
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