The Attraction of Opal Jewelry

Opal is non-crystalline and hydrated silicon dioxide. Opals have no definite shape, and can contain appreciable amounts of water. Water contents as high as thirty percent have been reported, although ten to fifteen percent is more the norm. Its specific gravity is quite low, ranging from 2 to 2.5. Sterling pendants with opal focal beads are quite common. These stones typically are quite light colored, and so they are sometimes paired with other more flashy gems such as rubies and sapphires. Mild colored specimens are generally less expensive than stones with bright and bold colors. Specimens with a bright luster are more desirable than dull ones. White opals are popular and quite common. At the other end of the spectrum, black opals are rare, sought after, and expensive.