The style, mood and presence from a single piece of jewelry depends on the composition created by its artist. The arrangement of color, shape and texture are elements each artist considers when they design their jewelry and many use gemstones to capture and illuminate their signature style.
Precious stones include diamonds, rubies, sapphires and emeralds. This designation reflects their rarity as well as their quality - they are transluscent with fine color in their purest forms. Their hardness is 8 - 10 on the Mohs scale.
All other gemstones.
the mohs scale:
This rates each stone on the basis of its innate hardness as well as the ability of one natural sample of matter to scratch another.