Dad loved to go fossicking. He would visit a friend who lived on the opal fields of Lightning Ridge, the heart of black opal country in Queensland, for a bit of a holiday. Black opal is the rarest and most precious of opals. On one such trip he found a likely looking stone. Chipping into it, he found it contained black opal. Unfortunately he had split it before he realised what he held in his hands. However, there was enough to make this ring and pendant which he gifted to Mum for their 40th wedding anniversary. They now belong to me.
“To think that you were the first person ever in the world to lay eyes on such a beautiful thing, that’s been there for a 140 million years, is just staggering, and to be the one that digs it out and gets to keep it is just fantastic.” Mark Jackson, Coober Pedy Opal Miner
A hundred years ago 14 year old William Hutchison found some surface opal. That was the beginning of the opal rush in Coober Pedy. What has followed is a cycle of boom and bust that marks the history of this outback town. By all reports opal mining gets into the blood much like gold mining. The drive to find that one elusive piece, the one that turns your life around, is compelling. And there are a handful who have struck it lucky.
Australia has 95% of the world’s supply of commercial opal, much of it coming from Coober Pedy, known for its white and crystal opal. Much of what is uncovered is potch – opal without fiery colour. However, about 10% is the vividly coloured, highly prized and sought after precious opal. One piece of good colour is enough to set you up for life.
The potch is left in heaped mullocks. Coober Pedy and surrounds is dotted with these hills ranging in size from small to huge. Popular for noodling, some locals make a living by going through the waste heaps looking for opal. And word is that some lucky few have struck it rich going through other’s trash. Because there are so hundreds of holes in the ground, many of which are abandoned mines, warning signs have been placed in the hopes that people walking in the fields take care and look where they step. Tourists are warned not to step backwards when photographing just in case they fall into one of the holes. Tragedies have occurred.
Opal is a hydrated amorphous form of silica. Its water content may range from 3 to 21% by weight, but is usually between 6 and 10%. Because of its amorphous character, it is classed as a mineraloid, unlike crystalline forms of silica, which are classed as minerals. It is deposited at a relatively low temperature and may occur in the fissures of almost any kind of rock, being most commonly found with limonite, sandstone, rhyolite, marl, and basalt. Opal is the national gemstone of Australia.
The internal structure of precious opal causes it to diffract light, resulting in flashes of colour. Depending on the conditions in which it formed, opal may be transparent, translucent or opaque and the background color may be white, black or nearly any color of the visual spectrum. Black opal is considered to be the rarest, whereas white, gray and green are the most common. In addition, opal may exhibit a form of iridescence. Being a soft gemstone, it should be handled with care. Because of its water content, raw opals in particular are stored in a container of water.
The “Olympic Australis” is reported to be the largest and most valuable gem opal ever found. It was found in 1956 at the famous “Eight Mile” opal field in Coober Pedy, South Australia. A miner working his claim found the opal at a depth of 30 feet. It was named in honor of the Olympic Games, which were being held in Melbourne at the time. This extraordinary opal consists of 99% gem opal with an even colour throughout the stone, and is one of the largest and most valuable opals ever found. The balance of 1% is the remaining soil still adhering to the stone. It weighs 17,000 carats (3450 grams) and is 11 inches long (280 mm), with a height of 4¾ inches (120 mm) and a width of 4½ inches (115 mm). It was valued at AUD$2,500,000 in 2005. Due to the purity of the opal it is anticipated that upwards of 7000 carats could be cut from the piece. However owing to it’s uniqueness, the opal will remain exactly as found.
“For in them you shall see the living fire of ruby,
the glorious purple of the amethyst,
the sea green of the emerald,
all glittering together in an incredible mixture of light”
Written by Roman Pliny in the 1st Century AD
© Raili Tanska