Understanding Gem Jewelry

Opal, October's birthstone, is sometimes considered the "Queen of Gems," because it encompassed the colors of all other gems. The Romans revered opal as a symbol of hope, fidelity, purity, and good fortune and held it to be second only to the prized emerald.

Opal is a non-crystalline gem that is formed in the ground when silica is liquefied and washed into fissures in the surrounding rock where it solidifies into a hardened gel. Tiny silica spheres create a pattern in opal that causes a prism-like effect that produces flashes of color.

Natural opal occurs in several types: White opal--the most common on the market--has a transparent or white body color with vibrant pastel flashes of rainbow color. Black opal has a blue, gray or black body color that reveals a more dramatic play of color. Boulder opal is most often black opal with some of the ironstone matrix in which it occurred still intact. Crystal or water opal is transparent, colorless opal that contains brilliant flashes of color swimming within it. Fire opal is transparent or translucent opal with a yellow to orange to red body color that may have a play of color or not.

On the Mohs scale of hardness, opal ranks 5-6.5. Opal contains a variable amount of water depending on the mine location and depth of extraction. This rather porous gem makes a poor ring stone because it is brittle and fragile. Thought should be given when designing jewelry that protects the stone from harsh wear.

Today, 95% of the world's opal is mined in Australia, known for producing the most spectacular material on the planet. White opal is also being produced in Brazil. Fire and crystal opal is found in Mexico and the United States (Nevada).

Use a soft dry or damp cloth to clean your opal. In fact, Rub the gem periodically with cloth moistened with olive oil to help preserve it. Do not soak your opal in place in chemicals or use mechanical cleaners. Avoid heat and dry conditions that could dehydrate and crack your opal. Treat it with care to prevent sharp blows and scratches. Avoid impacts. It is important to buy fine opal from a reputable retailer who will provide, in writing, all pertinent information regarding the gem including enhancements and special care notes.

Gemstone colors

Emerald - The greenest of the green, emeralds were cherished by the Romans above all other gems. Find out what makes this favorite of Cleopatra's so unique

Garnet - January's birthstone is famous for being as red as a ruby, but this colorful gem actually comes in every color but blue. Discover this elusive chameleon

Opal - Opals are the gem world's silvery mirrors, reflecting back every color in a flash of pastels or a streak of fire. Uncover this enchanting stone.

Peridot - Peridot is a gem that gets around. From ancient Egypt to present-day Apache mesas, even in space meteorites--you never know where its green gleam is going to show up.

Ruby - The color of courage and blood, rubies are even more precious per carat than diamonds. See why the Biblical authors to modern collectors use them as the measure of ultimate value.

Tanzanite- Millions of years in the making, deep-violet tanzanite revealed itself to humans only thirty years ago. Read about this newest discovery.

Sapphire - Blue as the perfect sky, sapphires have been used as protective talismans for centuries. Learn about the versatility of this stone that combines hardness and color variation like no other.

Tourmaline - Available in every color and saturation, this tough crystal has become a popular substitute for rubies, emeralds, and sapphires. Unmask this clever chameleon.

Turquoise - The lovely opaque blue of turquoise is produced by traces of copper in the stone. Elements of iron will also create a pretty, pronounced green hue. Oxides contribute to the stone's famous gray, brown or black veining.