Opal Dictionary

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     It is no wonder why early cultures from around the world have attributed magical properties to the opal. The mysterious patches of color that appear and disappear with every movement give opals a life of their own. Opals have been collected for thousands of years. The oldest opal artifact, estimated to have been collected at around 4000 B.C., was found in a cave in Kenya. Opals were one of the most highly prized gemstones to the Greeks and Romans. Early Greeks believed opals were the source of prophetic powers. As the Roman Empire grew, so did the demand for opals. A Roman Senator, Nonius, chose to be exiled rather than give his valuable opal to Marc Antony who wanted to give it to his lover, Cleopatra. A legend tells of a Roman Emperor who offered to trade one-third of his kingdom for a single opal. The Roman natural historian expressed his difficulty in describing the gem: "... it is made up of the glories of the most precious stones. To describe it is a matter of inexpressive difficulty: There is in it the gentler fire of the ruby, the brilliant purple of the amethyst, the sea-green of the emerald, all shining together in an incredible union." Opals have often found their way into the jewelry and crowns of royalty. Queen Victoria adored opals and kept a fine collection.

     While opals have always been an object of curiosity and mystery, the powers attributed to it have not always been positive. In the late 18th century, the opal was considered to bring bad luck to its possessor. The Spanish King Alfonso XII had given an opal ring to his wife who died shortly thereafter. The ring was passed on to family members and each person who wore it died mysteriously. Eventually, the king himself wore the ring and he too died unexpectedly. While historians will say that the deaths can be attributed to the cholera epidemic of the times, many have blamed the deaths on the opal.

Where are Opals found?

Common Opal is Common - Precious Opal is Precious
Opals are found on every continent and in nearly every country. Some pieces are hundreds of pounds, but the vast majority of it is what we term common opal, that is opal without any fire. And even of the small portion of opal that does have fire, most of it is unstable. Some examples of places that produce this kind of opal are; Rainbow ridge, California, Virgin Valley, Nevada, or Sencer, Idaho. Opal has to be both stable and have nice fire to be considered precious opal. Only a very small portion of naturally occurring opal can be considered gem-quality, and ninety percent of it comes from Australia. Some of the Australian opal fields are, Andamooka, Mintabie, Queensland, and White cliffs, but two of the more important opal producing areas in Australia are the Coober Pedy and the Lightning Ridge mining areas.

Australia is the largest producer of Opals in the world.
Click below to learn about two major mining areas in Australia.

Coober Pedy Mining Area          Lightning Ridge Mining Area

What determines an Opal's value?

Generally, boulder, matrix, assembled (doublets, triplets), man-made, and imitation opals are much less valuable than natural solid precious opal. Below are some factors that influence the price of natural precious opals.

1. Blind Angles: When an opal is rotated, if the color disappears at any angle, that angle is a blind angle. Many blind angles will depreciate the value of the opal no matter how bright the fire is from one particular angle. The worst blind angle is when the viewer is looking directly at the front of the opal.

2. Blind Spots: When an opal is stationary, the areas of the opal not displaying colors are blind spots. An opal with a smaller percentage of blind spots will generally be more valuable than one with a larger percentage. A valuable opal will have fire that covers most of the opal from all angles.

3. Brightness of Fire: The value of an opal goes up as the brightness of its fire increases.

4. Color Range: The kind of color the opal displays affects its value. Opals that display red fire are the most valuable. Opals that display blue-green fire are less valuable than those with red fire. Opals that only display blue fire are least valuable.

5. Fire Pattern: Opals with larger flakes of fire are more desirable than opals with smaller flakes.

6. Cutting Quality: Thicker opals will carry a premium because of increased durability. Regular shaped opals (oval) are more valuable than irregular shaped opals.

7. Background Color: White opals are the most common opals and typically less valuable than the rarer black opals. Black opals are the most sought after color.

How should I care for my Opal jewelry?

Opals are not as hard or as tough as other gemstones, so they can more easily be damaged. Never subject opals to extreme temperatures (eg. boiling water, freezer). Thermal shock can weaken or break your opal. If you wear your opal jewelry, it is unlikely that you will subject your opal to temperatures that will cause it to crack. Over time, an opal set in a ring will get scratched from normal wear and will need to be repolished.