Sapphires come in a wide range of natural colors and shades. Sapphires are available in every color but red. Sapphires in colors other than blue are often referred to as fancy sapphires. The most valuable sapphires have a medium intense, vivid blue color. Black, gray, or green overtones mixed in with the blue will reduce a stone's value. A more pastel blue would be less preferred than a vivid blue but would still be priced higher than an over dark blackish blue color. Color is mainly caused by the gemstone's selective absorption of certain wavelengths of light called the body color. In gemstones, color consists of three components:
Hue - the first impression of the color
Tone - the lightness or darkness of color ranging from light to medium to dark
Saturation - the intensity of a gemstone's color which is measured from dull to strong to vivid
Yellow sapphires are mined in Australia. Green sapphires come from Queensland. From Sri Lanka's gem-bearing gravels can be found sapphires in hues of royal blue, cornflower blue, pink, yellow, orange (a rare color), violet and gemstones with two or more colors. Yet gem dealers’ prize sapphires of a cornflower blue variety above all. Such stones, with a velvet depth to them, mined in Kashmir, are the most sought after due to their rarity. From Montana are mined a dark blue sapphire with a distinctive metallic sheen. Truly colorless sapphires are rare but are found in Sri Lanka, as are cloudy, milk-colored ones, which are called "geuda." Heat treatment is used to change the geuda into a blue stone.