Within the small family of jewels that “play with light”, opals surely claim top honors for variety as well as sheer beauty. The opal’s fascination deepens when one realizes just how many kinds there are and how they differ. From natural to synthetic to frank imitations, the range is nothing short of amazing.
All naturally occurring opals fall into one of two classes. Precious opals are the ones that produce flashes of iridescent color(s) when light strikes its surface at various angles. Any opal that does not exhibit colorplay is classified as common opal. Although both precious and common opals are made of the same material, it is the actual arrangement of all those microscopic crystals of silica that determines whether or not the stone will diffract light into various colors of the spectrum. Common opal does not have the optimum arrangement of crystals to produce this effect, but precious opal does. As the terms imply, precious opal occurs far more rarely in nature than does the other!
The internal structure of precious opal makes it diffract light; depending on the conditions in which it formed it can take on many colors. Precious opal ranges from clear through white, gray, red, orange, yellow, green, blue, magenta, rose, pink, slate, olive, brown, and black. Of these hues, the reds against black are the most rare, whereas white and greens are the most common. It varies in optical density from opaque to semi-transparent. For gemstone use, its natural color is often enhanced by placing thin layers of opal on a darker underlying stone, like basalt. Common opal, called "potch" by miners, does not show the display of color exhibited in precious opal.
Synthetic/lab created Opal
There is a difference between “synthetic” opal and “imitation” or “faux” opal. Synthetic opals are made in a laboratory from the same chemical (silicon dioxide) that occurs in natural opals. The process was developed in the 1930s and thus synthetic opals have been around for about eighty years! Some of them look very much like natural precious opal but there are several ways to tell them apart: (1) The colors in synthetic opal are usually brighter and occur in larger patches, often with a sort of ‘snakeskin’ pattern (2) Under magnification the color patterns will appear more regularly geometric than those in a natural opal and (3) The overall pattern appears more ‘neat and orderly’ than those in the naturally formed stones.
This includes every “opal-appearing” stone that is not made of (or from) silicon dioxide, hydrophane (Welo opal) or hyalite (water opal - which leaves us with the faux opals made of either glass, acrylic plastic, or resin.
Why should I buy synthetic opal jewelry?
Synthetic opal jewelry is an excellent alternative to natural opal jewelry for a number of reasons.
The first to spring to mind is the beautiful array of colors and patterns that are displayed in very rare natural opal are readily available in created opal.
The synthetic opal is much more durable and harder than its natural counterpart so breakages and longevity are also a plus.
Finally, the price. You can obtain a beautiful piece of opal jewelry for a fraction of the cost.
N.B. We list synthetic opal as OPALINE on our website. When we advertise genuine opal jewelry, it will be clearly stated in the description.