The Magic of Opal Gemstones
What do soap bubbles, oils spills on wet roads, butterfly wings, and seashells have in common with the opal gemstone?
Iridescence is a natural phenomenon that evokes feelings of magic and mystery. The surfaces of iridescent objects appear to be changing colour gradually as the surface is viewed from slightly different angles. This change of colour is caused by microstructures in the material that interfere with light. In fact, in Greek, opal means ‘to see a change of colour’. Their iridescence has been noted throughout history, with most civilisations seeing opal as a lucky gemstone, and in 75 AD, the Roman Scholar Pliny wrote:
“Some opali carry such a play within them that they equal the deepest and richest colours of painters. Others…simulate the flaming fire of burning sulphur and even the bright blaze of burning oil.”
He wondered at the fact that this kaleidoscopic gem encompassed the red of ruby, the green of emerald, the yellow of topaz, the blue of sapphire, and the purple of amethyst.
- Since the discovery of Opal in Australia in 1850, it has become the national stone of Australia where 96% of the world’s precious opal comes from.
- For those lucky enough to be born in October, the opal birthstone is regarded as protective, keeping the wearer from harm.
- Opal is a hydrated, amorphous form of silica. After a rainfall, the water that seeps down into crevasses in rocks evaporates and the silica that is left behind dries out and hardens into precious opal. Sometimes, silica seeps into spaces around wood, seashells and skeletons, resulting in opalized fossils.
- Traces of opal were found in the Martian meteorite which fell in Egypt in 1911. These traces of opal were seen as evidence of water existing on the planet, and therefore potentially life. In 2000, images from NASA confirmed that water did once flow on Mars.
- The most expensive opal of all time is the Virgin Rainbow, which was valued at over $1 million.
In the west, these precious stones are commonly set in opal jewellery. Opal rings, earrings and necklaces are especially popular and are treasured tokens of hope and good fortune.
Opal can come in a variety of types and colours, with black opal considered to be the rarest while white, grey, and green are deemed the most common. White opals can look serene, graceful, and pure set in a yellow gold ring and paired with diamonds, as in this opal and diamond cluster ring.
Black opals, however, are best suited to white gold or platinum where they can stand out and create a sharp, dramatic contrast. This mid-century black opal solitaire ring demonstrates the wondrous iridescence that black opal can feature, and is complemented by a unique sweeping white gold shank.