The Story Behind the Stone: Bould’ Over

Countless gemstoneshave varieties or sub-sets which can subtly or dramatically differentiate each stones' appearance from one another; yet their basic chemical makeup remains the same.

Take opal for instance. This amorphous mineral species lists thirty-six varieties in the venerated "Gem Reference Guide," produced by Gemological Institute of America (GIA), used for reference in their colored gemstone program. Thirty-six, that's an impressive line-up for any gemstone.

Some of these variations are well known, like white opal, which is translucent to semi-translucent exhibiting a play of color against a white background. Black opal is described the same way except that those plays of color rest on a dark ground, which could be black, gray or even blue. Most people in the trade recognize fire opal, as do consumers, especially fans of television shopping shows which have popularized the lesser known gemstones, making household names out of stones like kyanite.

I'm not sure I'd recognize an obscure opal variety like Louisiana opal which the "Gem Reference Guide" explains is a rock principally composed of quartz, opal and pyrite. That's an interesting combination, and perhaps an edgy designer somewhere is working that stone into their next collection. But what I am seeing lately with couture designers are other exciting opal choices. We're talking boulder opal, matrix opal, and even tree replacement opal. What was previously a collector's curiosity for the bookshelf or rock hound's display are now fast becoming the main attraction in top notch original jewelry.

A few things may be driving this trend. The green push in jewelry focuses on organic gemstone choices in their original, or close to it, crystal form. Boulder opal is an interesting material showing play of color opal randomly woven throughout its matrix of ironstone, a durable and dark opaque substance. Pricier jewelry always carries a greater expectation of being unique in some way, and these opal choices fit perfectly into this prospect.

Jarrett-March-BruniniOpal in matrix - or matrix opal - exhibits beautiful play of color freely intertwined with an opaque light toned matrix. Tree (or wood) replacement opal is less frequently seen and eye-catching with its juxtaposition of a fine organic gem grown into the hollows of ancient wood.

Katey Brunini (K. Brunini) uses the medium of jewelry to create individual sculptural works of art, and wood replaced opal appears in her distinctive collection of stylish rings. They are a perfect focal point to her important rings which include precious colored stones and diamond in 18 karat gold.
(image right: K.Brunini's "Skipping Stones" bracelet with wood replacement opal, bezel set in 18K yellow gold and 1.30 ctw green diamonds. Courtesy K. Brunini Jewels.)

Irene Neuwirth's brand epitomizes the wearable art form. Notice in her recent collection, which features opal, the stone is the thing. The fine gold mounting perfectly frames the natural beauty of her carefully chosen stones; but they never upstage the opal.

Jarrett-March-ParleParlé Gems embraced several varieties of opal in their line recently, and boulder opals are prominently showcased in their gold and diamond jewelry line. According to Parlé, boulder opals are like ancient rainbows, because these gems are the result of material preservation of some 60 million years ago. "These natural gems each have their own individual character" and so Parlé feels that each creation exhibits a "personal jewelry expression." (image above:Parlé Gems creates 14kt yellow gold and diamond pendants in boulder opal. Courtesy Parlé Gems)

You may be perplexed as to what can motivate your clientele lately. With a burgeoning focus on ‘green' jewelry, these opals present natural organic choices for your customer. You will also want to underscore the fact that most colored gemstones undergo treatments now; here are alternatives that require no enhancements to them. And finally in an age where volume manufacture is the norm, the exact same opal will never be seen on anyone else - allowing your customer to feel confident about their choice in gemstones and in retailers.

Graduate Gemologist and Registered Master Valuer Diana Jarrett is also a member of the National Association of Jewelry Appraisers (NAJA). She's a frequent lecturer at conferences and trade shows. Jarrett serves as Colored Stone Editor for Rapaport Diamond Report; with other works regularly appearing in trade and consumer publications. Contact her at This email address is being protected from spambots. You need JavaScript enabled to view it. or visit her website: