Stones · Studio

Opals: who knew?

I’ve never been the slightest bit interested in working with opals.    The hue of old milk with bits of anemic color feebly attempting to glimmer through?  Petrified yak snot would probably be more interesting.

But recently a client asked me to design a pendant with opal, and so I went researching, hoping to come up with something, anything,  I could use to create a beautiful piece for her.  I wasn’t optimistic, but boy, was I wrong about opals.  I’m in love.

Black opal 7 x 5 mm
Black opal 7 x 5 mm

At first glance, the gem world breaks down roughly into diamonds and colored gems.  Dealers of one rarely specialize in the other, too.  Colored gem dealers might carry a few opals, and those are usually of the underwhelming milky type.  Go digging, though, and you’ll come across the world of opal dealers, who cut and carry a range of opals most of us don’t know exist.  My client wanted an Australian opal, a distinct subtype of the gem, and within this category?  Even more subtypes.

Opals, unlike most other precious gems, are not colored by mineral coloring, and are not crystalline in structure.  Opal is hydrated silica, and when viewed under magnification opal’s structure is that of tightly packed strings of spheres.  Opal’s color play is due to how these spheres reflect the light spectrum. Larger spheres reflect the longer wavelengths of oranges and reds, smaller spheres reflect the shorter wavelengths of blues and greens.


Semi-black opal 11x 7
Semi-black opal 11x 7 mm

The stones I’ve fallen in love with are the black and semi-black Australian opals.  These stones are among the rarest of opals, and offer intense, brilliantly flashing color: cherry reds, peacock blue, acid greens and fiery oranges.  Black opals have a “body tone” of deep gray to black (a base layer of dark stone) and the color-play of the opal is made more visible because of this dark background.  The milky-white opals most of us are most familiar with are on the opposite end of this spectrum.

Alright, so I’ve fallen in love with opals…..what about that old superstition: Opals are bad luck to wear if they aren’t your birthstone?  Opals were bad luck.  To gem cutters.  Historically, gem cutters were required to pay for any stones which broke during cutting.  Opals are rat bastards to cut.  Remember their structure?  Hydrated silica.  They don’t cleave (split) along straight lines.  Cutting opals could result in a gem cutter owing a lot of money in damages, and that’s bad luck.   Most superstitions begin with the tiniest grain of truth, and this truth was probably the grain which got that tale started.  That, and stingy people born in October who don’t share well.

In Australia, the Aboriginal folklore says that opals were created when a rainbow fell to earth, and that’s not bad luck at all.


Semi-black opal 8 x 5.5
Semi-black opal 8 x 5.5 mm
Semi-black 9x 5 mm
Semi-black 9x 5 mm

Thanks to for the wonderful information on opals they provide on their webstie.  These images are stones from their stock, and were available for purchase at the time this article was posted.  If you have an hour or five to get lost in the world of opals, this is where I fell in love:


6 thoughts on “Opals: who knew?

  1. Great photograph examples of Opals from Australia you have on your page , I was the last man to work with the brothers that found the largest black Opal in modern times, from the capital of the black Opal industry lightning Ridge Australia. You can view images of the Guineas book of record Opal which is known internationally as the Halley’s Comet and is over 2000 carats at .
    You are also welcome to use our images of Opal gem stones from our web site for your page.

  2. Opal is my Mom’s birthstone and the ones you have shown on your site are gorgeous! I had no idea that they could be so colorful, I thought they only were milky white with just a little bit of color. Wow.

    1. And those are just one type! Carla commented that she likes boulder opals, which have some intense color play, and Jean linked to African opals, which are white with strong color play.

      Opals can get really, really expensive, but all the stones shown in this post are in the $50-$150 range, and are solid opal (always check to see that it’s a solid stone). It’s totally doable.

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