Written by Modern Jeweler On May 2, 2013.
Opal was highly valued in Ancient Rome. But the gems they treasured wouldn’t rate a second glance today. The opal of the ancient world was a cloudy white gem with a few subtle pin pricks of play of color. This opal was mined in what is now the Czech Republic, near Czerwenitza.
Since the discovery of Australia’s incredible opal deposits in the nineteenth century, the standard for beauty in opal has been redefined. Australia’s opals have more fire, more transparency, and more abundance than the ancients dreamed possible. Thanks to the richness of Australia’s deposits, white opal has become a staple in affordable fine jewelry. The average consumer can own an opal that would put the opals of emperors to shame.
Pretty For Pennies
Mass merchandisers have found opal an ideal choice for affordable jewelry, especially earrings and pendants. For extremely little money, white opal provides a beautiful gem, that is unique, thanks to its individual pattern of play of color. According to a New York dealer, the most popular types of white opal in the mass market are: 1) milky white with pale multi-colored pinfire, or 2) blue green with broad flashes of color.
Because a large amount of low-end opal is used in earrings, pinfire is more popular than broad flash: it’s easier to match pairs.
Up The Ladder
Consumers who pride themselves on wearing quality will probably not be happy with largely opaque, pale, no-color-play opal- no matter how cheap. This opal hardly lives up to its name, derived, in part, from the Greek word opallios, which means “to see a color change.” But to get stones with an interesting array of color, plus some translucency, expect to pay a lot more than is asked for run-of-the-mill anemic opal. Stones that boast strong foreground reds, greens and blues are definitely not available at trinket prices.
The next step up is what dealers call “crystal opal.” This term refers to the look and not the structure of stones. These opals sport, in one dealer’s words, “a translucent glass-like appearance with full colors seemingly suspended in a transparent base.”
But “crystal opal” is only one of the varieties of better opal. The finest usually show no identifiable background color, just a continuous, unbroken array of vivid color patches or patterns. These stones will cost about the same as better aquamarine or imperial topaz.
Although commercial-grade opal is largely what jewelry manufacturers use these days, there seem to be strong stirrings of collector interest in better opal.
Improving the Odds
Opal has a weakness: some stones eventually crack because of structural weaknesses made vulnerable by heat and dehydration. But the problem can be minimized by dealer quality control.
First, the knowledgeable dealer knows which locations in Australia produce the most stable opal (Andamooka is famous for such stones), and shops accordingly. As an extra safeguard, most dealers hold all polished stones for several weeks and return any that crack.
Second, because those opals that crack tend to do so sooner rather than later, the responsible dealer will refrain from selling newly purchased or polished stones for a certain period of time to let nature weed out any losers. Dealers we interviewed call this procedure “curing” and subject both rough and cut stones to it.
Unfortunately, the dealer’s ounce of prevention can be undone by abuse in display cases.
Since those opals with a high water content are the most prone to cracking (also called “crazing”), prolonged exposure to bright lights in a closed, unventilated showcase is an invitation to trouble. Thankfully, cracks are often skin deep and can be buffed out on a polisher’s wheel.