While most of the world's opals are mined in the Australian outback, price-conscious Australians buy most of theirs in Hong Kong. Why?
The reason is because this bustling city is the world's leading opal market, with prices per karat of opal about 30% to 40% less than in Australia, 50% less than in the United States.
Some superstitious people think that opals are unlucky--unless they're your birthstone (October) or are given to you as a gift. Superstition or not, opals are a very lucky buy in Hong Kong, where top-quality stones are processed--then sold loose, as magnificent pieces of jewelry or carved into exquisite statuettes and other objets d'art.
Prices are so reasonable that opal fanciers and dealers from around the world come to Hong Kong to buy these fiery stones that capture the imagination with their rainbow of opalescent colors.
Hong Kong became an opal center about 20 years ago, when several Australian traders brought some rough stones to the Crown colony to have them cut and set.
Hong Kong's sizable pool of experienced and low-paid gem cutters made processing these roughs into lustrous gems much less costly than it would have been in Australia. A new industry was born.
From 1970 to 1975 about 200 small, independent opal factories operated full time here. In recent years Australian mines have produced a smaller volume of opals, so that now there are about 30 opal factories, most with fewer than 20 employees. They are keenly competitive in supplying top-quality processed opals at reasonable prices. The value of an opal goes up about 20% annually.
Opals are among the world's prettiest gemstones and among the most misunderstood.
Until the 1960s, scientists thought their brilliant colors were from the refraction of light from the stones' thin surface layers. The real cause was discovered under an electron microscope using a magnification of 20,000!
Basically, an opal consists of thousands of minuscule, uniformly shaped spheres of the mineral cristobalite, densely layered in siliceous jelly.
Chemically, opals are somewhere between ordinary sand and harder quartz. Opal's iridescent rainbow of colors comes from light passing through the cristobalite spheres and spaces between them. As a stone is moved, changing angles of refracted light create a dazzling display of glowing reds, yellows and blues underneath the stone's polished surface.
Opal's special properties make the stone challenging to cutters. It is softer than diamonds and colored gemstones, and does not have their crystalline structure.
To bring out the full range of fire and color, opal roughs are cut and polished into smooth, round shapes, rather than faceted like diamonds or colored gemstones. Even a stone that is almost flat may have an extraordinary brilliance.
Opal contains up to 30% water. Dry storage conditions may allow evaporation, which may lead to cracking. To prevent this, loose gems are often stored in water or oil. During and following setting, stones must be kept away from excessive heat and dryness.
Hong Kong dealers sell all types of Australian opal, including the most precious black ones that are mined in Lightning Ridge. Also, light opals from Coober Pedy and Andamooka mines in South Australia and Mintabie opals with their fiery cross inclusions.
Avoid being duped into buying synthetic or treated stones, and beware of sellers who offer doublets (a thin slice of light opal joined to a dark background of stone, called \o7 potch\f7 ) or triplets (same as a doublet, but with a thin slice of quartz over the opal) as solid opals. Check opals under light for signs of cracking and/or ridges of dirt within the stone.
Buy from reputable jewelers. Those displaying the Hong Kong Tourist Assn. emblem, a red decal of a Chinese junk, meet the association's strict standards. If problems occur, the association's complaints unit will investigate.
For the best selection of stones and styles, go to specialists.
One of the largest of these is Opal Creations (Burlington House, ground floor inside the arcade, 92 Nathan Road, Tsimshatsui), featuring more than 2,000 jewelry designs with opals set in 14- or 18-karat gold, often in combination with diamonds and colored gemstones. These range from very modest souvenir items to high-ticket extravaganzas.
For example, earrings cost about $40 to $400, depending on size and quality; shapes include ovals, hearts, rectangles and teardrops.
Earrings in floral or butterfly settings (about $90 and up) have matching pendants (about $120 and up). Large pendants in traditional or contemporary settings cost $1,200 to $2,500. Opal cameos cost $100 and up. Jewelry sets ($700 and up) of earrings, ring, bracelet and necklace are displayed in pretty red leather boxes. Cuff links cost $300 to $600.
The price for 16-inch strings of round opal beads is about $250, flat-shaped beads (87 karats) with a 14-karat gold clasp cost about $700, and necklaces with opals set in 14-karat gold cost $850 and up.