What is a sapphire?
Sapphire is a gemstone variety of the mineral corundum, an aluminum oxide. Trace amounts of other elements such as iron, titanium, chromium, copper, or magnesium can give corundum blue, yellow, purple, orange, or a greenish color. Chromium impurities in corundum yield a pink or red tint, the latter being called a ruby.
The sapphire is considered one of the four precious stones, together with the ruby, the emerald and the diamond. Sapphires have a hardness of 9.0 on the Mohs scale of mineral hardness. Among the natural gems only moissonite and diamond are harder, with diamond having a Mohs hardness of 10.0 and moissonite falling somewhere in between sapphire and diamond in hardness.
The sapphire is one of the three gemstone forms of corundum, the other two being ruby – defined as corundum in a shade of red—and padparadscha—a pinkish orange variety. Although blue is their most well-known color, sapphires may also be colorless and they are found in many colors including shades of gray and black.
The sapphire is considered one of the four precious stones, together with the ruby, the emerald and the diamond. Sapphires have a hardness of 9.0 on the Mohs scale of mineral hardness. Among the natural gems only moissonite and diamond are harder, with diamond having a Mohs hardness of 10.0 and moissonite falling somewhere in between sapphire and diamond in hardness.
The sapphire is one of the three gemstone forms of corundum, the other two being ruby – defined as corundum in a shade of red—and padparadscha—a pinkish orange variety. Although blue is their most well-known color, sapphires may also be colorless and they are found in many colors including shades of gray and black.
