Synthetic ruby

Synthetic Ruby

Chemically it is aluminum oxide (Al2O3) with a small amount of chromium oxide (Cr2O3)added as a colorant. Depending on the amount of chromium oxide added, the color varies from light pink to dark red. There are a number of methods utilized to make synthetic ruby. They include melting the ingredients (Al203 melts at about 2,050 degrees centigrade), and then slowly cooling so thet the material crystallizes. Some people disolve the Al2O3 and Cr2O3 in a flux at much lower temperatures, and then crystallize from the dissolved ruby. Synthetic ruby is used as the 'active' part in some lasers, as a gemstone, and in many areas where a hard, chemically resistant material is needed such as bearings in various instruments and watches. ( Typically the 'jewels' in a watch movement are synthetic rubys.) Even though the mixture of Al2O3 and Cr2O3 (when disolved or melted and subsequently crystallized0 is called a synthetic ruby, it is definitely not the exact same composisition as that of naturally occuring ruby. Natural ruby contains up to 30 different elements (most in small quantities) along with the Al2O3. These elements cause the color of natural ruby to vary widely and generally to look considerably different in color than any synthetic ruby. There is a company in the USA that actually uses small crystalline pieces of genuine ruby. The small crystalline pieces of natural ruby File:NaturalSmallRuby.jpgare melted in an iridium crucible and then the crucible is slowly cooled so that the 'ruby liquid' recrystallizes into one large single crystal of ruby.