Rubies come in a wide range of natural colors and shades of red. The color range includes pinkish, purplish, orangey and brownish red depending on the chromium and iron content of the stone. The most valuable rubies have a vivid, medium-dark red to slightly purplish red color. Many fine rubies from Myanmar have a slight purple secondary color. Color is mainly caused by the gemstones’ 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