The word sapphire comes from the Greek translation for blue and was used in ancient times to describe any blue stone, often lapis lazuli. Around 1800 it was discovered that sapphires are a gem variety of corundum, the other being ruby. Corundum is a hard stone, rating a 9 on the Moh’s scale, making it the second hardest natural mineral. Its chemical composition is aluminum oxide. The many colors in which corundum occurs are due to the presence of other trace minerals. Blue coloration is caused by the presence of titanium and iron, a violet stone is colored by vanadium, and slight iron content produces a yellow stone. Pink is caused by chromium, and iron plus vanadium results in orange stones. Colored sapphires are referred to as Fancy Sapphires in the gem trade. It is common in the gem trade to heat the sapphires to enchance the colors.