Ruby Precious Stone

     A ruby is a pink to blood-red gemstone,a variety of the mineral corundum aluminium oxide. The red color is caused mainly by the, presence of the element chromium.its name comes from ruber,Latin forred.Other varieties of gem -quality corundum are called sapphires.The ruby is considered one of the four precious stones,together with the sapphire,right the emerald, and the diamond. Prices of rubies are Primarily determined by color. The brightest and most valuable "red" called pigeon blood-red,commands a huge premium over other rubies of similar quality. After color follows  clarity: similar to diamonds a clear stone will command a premium, but a ruby without any needle-like rutile inclusion will indicate that the stone has been treated. Cut and carat also determine the price. Rubies have a hardness of 9.0 on the Mohs scale of mineral hardness.Among the natural gems only moissanite and diamond are harder, with diamond having a Mohs hardness of 10.0 and moissonite falling somwhere in between ruby and diamond in hardness.
All natural rubies have imperfections in them,including color impurites and inclusions of rutile needles knows as "silk". Gemologists use these needle inclusions found in natural rubies to distinguish them from synthetics,simulants, or substitutes. Usually the rough stone is heated before cutting.Amost all rubies today are treated in some form, with heat treatment being the most common practice. however, rubies that are completely untreated but still of excellent quality commanda large premium.