Sapphire is usually associated with the color blue. In fact, blue sapphire is the most common color of sapphire and is highly valued as a precious gemstone due to its bright, deep blue hue. However, sapphires can come in a variety of other colors as well, including pink, yellow, green, purple, and even colorless (known as "white sapphire"). The color of sapphire is determined by the presence of trace elements such as iron, titanium, and chromium in the crystal structure of the mineral corundum, which is what sapphire is made of. Different trace elements can give sapphire its different colors.