The Opal
The “Queen of Gems,” famed for its vivid, kaleidoscopic play-of-color and mystic allure.
Overview
Opal is a gorgeous semi-precious gemstone that has been alluring people for centuries. It is famed for showcasing a vivid "play-of-color"—an optical phenomenon caused by millions of tiny silica spheres that diffract light, making the gem flash various hues and patterns as it moves. This characteristic makes every single opal entirely unique.
While green, white, and blue-toned opals are commonly available, those displaying black and red hues are extremely rare. Approximately 97% of the world's opal supply comes from Australia, where it serves as the national gemstone, though it is also mined in Mexico and several other countries.
Symbolism
Few gemstones possess folklore as rich as the opal. Aboriginal tribes believed it was born from a rainbow brought to earth by the creator. The Romans associated it with fidelity, hope, and purity, while the early Greeks believed it could foretell the future.
Despite a brief drop in popularity in the 1800s due to a superstitious novel, Queen Victoria famously revived its status by gifting opals to her daughters. Today, William Shakespeare's description of it as the "Queen of Gems" in his play Twelfth Night holds true as it continues to lure people with its sheer beauty.
Physical Properties & Quality
Hardness & Strength
Opals are delicate, scoring a 5.5 to 6.5 on the Mohs scale. They are susceptible to scratches and breakage. Surface cracks (crazing) can reduce value, while deeper fractures render them unsuitable for jewelry. Additional care is required if you intend to wear an opal daily.
Treatment
While generally untreated, white, gray, or black opals are sometimes enhanced using the sugar and smoke methods. This involves immersing the gem in a sugar solution/sulfuric acid or wrapping it in paper and subjecting it to smoke, which darkens the background and makes color flashes pop.
Color & Clarity
Value is driven by the number and clarity of different hues present in its play-of-color. Blue and green are common, but warm tones (orange, pink, yellow, red) shoot the price up. The clarity is influenced by transparency and a lack of natural inclusions (sand, chips, or matrix).
Cut & Carat Weight
Unlike faceted stones (sapphires, emeralds), opals are typically cut into rounded, smooth cabochons. This shape best showcases their play-of-color. Occurring naturally in a variety of sizes, opals are priced per carat, with the overall size influencing the final value.
Opal Grading System
Top 1%
Milky with a highly vivid play-of-color, only the top 1% of remarkable opal stones belong to this category. They are opaque and completely surface-clean.
Top 10%
This category comprises the top 10% of opal stones. They are milky and display a medium play-of-color, with only very slight surface blemishes.
Top 33%
Representing the top third of available opals, these are milky and opaque in appearance, displaying a lower play-of-color and slight surface blemishes.
Top 75%
This entry-level category includes opals that are milky with little to no play-of-color. They are opaque and feature visible surface blemishes.
Opal Care Instructions
Opals contain varying amounts of water in their composition. If they dry out, they can lose their gleam or even crack. Keep the following tips in mind to maintain their delicate beauty:
- Avoid Extreme Temperatures: Sudden heat or freezing cold can severely harm an opal. Never use hot or boiling water for cleaning.
- Gentle Cleaning: Use only a damp, soft cloth and mild cleanser. Harsh chemicals, bleach, or abrasive agents must be strictly avoided.
- Natural Moisture: During regular wear, the natural moisture from your skin actually helps keep the stone from drying out!
- Long-Term Storage: If storing for an extended period, seal it in a plastic bag with slightly dampened cotton wool to help the stone retain its moisture.
- Store Safely: Use a soft cloth bag for regular storage to prevent it from being scratched by harder jewelry.