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December 1999

Gemstones & Pearls: News

Phenomenal Opal

One of America's finest gems comes to light

When Thomas Ames sat down to carve one of the largest and finest opals mined from Opal Butte, OR, you can only speculate about his state of mind. A seasoned glyptic artist, Ames was about to use his particular technique of sand-blasting a gemstone – masking off strategic areas, blasting, remasking and so on – until the opal yielded to the varying depths and contours of the Cattleya-laelia orchid design he wanted to create.

But this wasn't a normal opal. First, it was huge – over one pound of rough. It also had an unusual quality. "It was unlike Australian material, which is opaque and shows its play of color in reflected light," says Ames. "This piece had a clarity I've never seen in opal before; I could see through it, and the fantastic play of color dazzled me."

The opal also has some interesting rounded orange clouds that some gemologists speculate are concentrations of microscopic iron oxide stains, similar or identical to the colors seen in cherry opals.

Ames says the opal is of the contra-luz variety, the Spanish phrase meaning "against the light." The opal composition (microscopic, tightly packed silica spheres) diffracts reflected and transmitted light, resulting in red, orange, green, blue and violet flashes and pinpoints of color. This compostion creates an ebb and flow to the colors as the gem is rotated and angled in relation to light.
In addition to the opal's composition, Ames considered its general outline. "Cut just right," he says, "it has a rainbow-opal effect." (Rainbow opals typically change body color entirely, depending on how light is angled in relation to the gemstones.)

Award-Winning Result

What resulted from Ames' tireless efforts was the 272-ct. opal carving shown here. The gem won a first-place honor in the American Gem Trade Association Cutting Edge competition this year (see Professional Jeweler, October 1999, p. 62).

"It was the largest piece mined at the Blue Mountain range in Oregon until just last year," says Ames. "Now a 2-pound piece of pure transparent opal has been cut from the matrix, though it remains unfashioned."

Almost 2000 years ago, naturalist and philosopher Pliny the Elder pondered the virtues of opal. He wrote in his epic Natural History volumes: "There is in them a softer fire than in the carbuncle [garnet]: there is the brilliant purple of the amethyst; there is the sea-green of the emerald – all shining together in incredible union."

It's an appropriate salute to Pliny two millennia later. A singular opal, from a world unknown to him, that perfectly matches his contemplations.

  • Thomas Ames, Arvada, CO; (303) 424-3772.

by Robert Weldon, G.G.

272-ct. opal from Opal Butte, OR, was carved by Thomas Ames. Photographed with transmitted light, this opal reveals that it is the contra-luz variety.

Copyright © 1999 by Bond Communications.


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