The hardness of sapphire (9 on the mohs scale) and it’s wide variety of colors makes it a most desirable gemstone for jewelry. Blue is the preferred color, however it comes in violet, green, yellow, orange, pink, purple, and intermediate hues. Some stones exhibit the phenomenon known as color change, most often going from blue in daylight or fluorescent lighting to purple under incandescent light. Sapphires can even be gray, black, or brown.
Kashmir, is considered intensely saturated and velvety. Rare sapphires from Kashmir set the standard for blue.
Royal Blue is the world’s most famous engagement ring: Kate Middleton’s and Princess Diana’s sapphire!
Padparadscha is a rare and valuable pinkish orange sapphire. It’s name is derived from the Singhalese word for aquatic lotus blossom, which has an unusual salmon color.
There are a number of processes used to alter the color, clarity, or improve the durability of gems. Heat treatment is the most common alteration in sapphire.