Description

ruby, a gemstone composed of transparent red corundum (q.v.), a mineral form of aluminum oxide, Al2O3. Its color varies from deep cochineal to pale rose red, in some cases with a tinge of purple; the most valued is a pigeon-blood red. The red color arises from the replacement of a small number of aluminum atoms by chromium atoms (1 in 5,000). High refractivity is characteristic; when cut and polished, ruby is a brilliant stone, but, because it has weak dispersion, it lacks fire. On exposure to high temperatures, ruby becomes green but regains its original color upon cooling. When subjected to radiant discharge, ruby phosphoresces with a vivid red glow.

Ruby is a mineral of very limited distribution. Its best-known localities are in north-central Myanmar (Burma), northeast of Mandalay, where the gemstone occurs in bands of crystalline limestone associated with granitic and gneissic rocks. Rubies have been found at several localities in Thailand, in gravels with sapphires and spinels; they are generally of dark color, often inclining to a deep reddish brown. Rubies found in the gem gravels of Sri Lanka are not usually of such good color as the Myanmar stones.

Ruby, a gemstone composed of transparent red corundum (q.v.), a mineral form of aluminum oxide, Al2O3. Its color varies from deep cochineal to pale rose red, in some cases with a tinge of purple; the most valued is a pigeon-blood red.

Project Description

Ruby, a gemstone composed of transparent red corundum (q.v.), a ...

Release Date:

10/31/2022

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Customers

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Author:

Temesgen woldemariam