SAPPHIRES

Sapphire (Greek: σάπφειρος; sappheiros, "blue stone"^[1]) is a gemstone variety of the mineral corundum, an aluminium oxide (α-Al₂O₃), when it is a color other than red or dark pink, in which case the gem would instead be called a ruby, considered to be a different gemstone. Trace amounts of other elements such as iron, titanium, or chromium can give corundum blue, yellow, pink, purple, orange, or greenish color. Pink-orange sapphires are also called padparadscha. Pure chromium is the distinct impurity of rubies. However, a combination of e.g. chromium and titanium can give a sapphire a color distinct from red.