What Are Opals?
Opals are a non-crystalline gem, formed from liquid or gelatinous silica. These October birthstones are relatively soft in comparison to diamonds, with approximately the same hardness as glass. Opals contain 6-10% water and are non-porous, unable to soak up more water, oil, or any other substance.
Opals are relatively fragile and will crack under extreme heat or very low humidity. These gems should not be cleaned by using an ultrasonic cleaner, and may need re-polishing to maintain their luster over a long period of time.
In ancient times, opals were considered extremely lucky and were worn as talismans to ward off disease. In the early 19th century, however, diamond merchants, hoping to increase their gem's value, started spreading rumors of the bad luck that would come to wearers of the opal. Today, most (if not all) superstitions surrounding the stone have been dismissed, and the opal is once again considered a favored gem.
Kinds of Opals
Two varieties of opals are found in nature. First, the common opal or ┬?potch┬? is the dull white, gray, or black opal that comprises about 95% of all of the mined opal in the world. The common opal is abundant throughout the world, but they are valueless on the gemstone market.
The second variety of opal is called the precious opal. Known for their unique spectrum of color and unusual patterns, these rare opals are the gems that you will see showcased in fine jewelry. Black opals are the rarest of the precious opals and can be more highly valued per carat than the finest diamonds. Precious opals are almost exclusively mined in Australia, and are sometimes also referred to as sedimentary opals.
The value of an opal is determined by several factors, including the following:
- Body Tone: the underlying color of the stone; black or dark colors are most desirable, with lighter colors being less valuable.
- Brilliance: the brightness and clarity of the stone.
- Pattern: color variances within the opal that can appear like a picture within the stone.
- Color Bar: the thickness or depth of color within the stone.
- The Play of Color: the full spectrum of color shown as white light is diffracted off of the opal. The red or fire opal is the rarest of colors and generally more valuable than opals that appear to be blue or green.
- Faults: anything that detracts from the value of the stone, such as a crack or a potch line.
- Jewelry such as earrings, rings, tie tacks, cuff links, necklaces, hair pieces, broaches, and bracelets
- Rough opal specimens
If you are seeking an opal to give as a 34th anniversary gift, savor the rainbow of colors and original beauty that nature has provided in the form each gorgeous stone. Give your gift knowing that you have truly chosen a "one of a kind" present.