October Birthstones: Opals & Tourmalines

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Choices, choices! Those of you blessed with an October birthday have two fine selections for stones: the opal and the tourmaline.


There is nothing ordinary about an opal! They range in hue from the familiar pearly white to vivid blue, black, yellow and even orange. Orange seems strange, doesn’t it? The first time I encountered one of these beauties during my class work at the Gemological Institute of America (visit GIA at  http://www.gia.edu/) in Carlsbad, CA, I literally couldn’t believe my eyes. This brilliant orange gemstone is called a Fire Opal and they come from Mexico.

Opals are born when seasonal rains drench dry ground and soak into ancient underground rock, carrying with it dissolved silica (sand). As the water evaporates, solid silica deposits are left in the cracks and between the layers of underground sedimentary rock forming opal. The beautiful play of colors that shimmer beneath the surface of precious opal is the diffraction of light passing through the silica spheres.

While Australia produces more than 90 percent of the world’s opal, recent deposits have been mined in Ethiopia. If you stop by the store, we would be happy to show you a lovely new Ethiopian opal pendant on display!


Another instance of “I can’t believe my eyes” frequently occurs around the store when customers are viewing tourmaline. Its glowing green shade is frequently mistaken for emerald. We are quick to educate about this lively mineral!

Most gem tourmalines hail from the mineral species elbaite, which are rich in sodium, lithium, aluminum, vanadium and sometimes copper. They occur in granite-containing pegmatites, which are rare igneous rocks.

A transparent stone of many colors, tourmaline is dichromatic; it shows a bright color from one direction but will look almost black when seen from the side. The tourmaline comes in many colors from many shades of green and pink to reddish-purple and orangey-red. One of my favorites, the watermelon tourmaline, occurs in nature with a pink center that blends to a green exterior. Jewelers typically cut this material in slices to make the most of this colorful array. Visit our birthstone case and we will be happy to show you our luscious watermelon tourmaline pendant.

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