What Makes Opal . . . Opal?
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| Stambolian Peruvian Pink opal and pearl earrings. 1stDibs |
Think of opal, and undoubtedly a white opaque cabochon stone with rainbow flecks of color comes to mind. You'd be right of course.
So Much More
But there's so much more to opal, and some of its examples would escape anyone's perception of true opal. So what exactly makes an opal, an opal?
Opal's Curious Composition
First off, it's the material which collectively heaps all opal varieties together. And that is a hydrated silica. It is not organized in a crystal habit like most hard gemstones. Under high magnification, the interior set up of opal looks like a massive array of micro-miniature bubbles.
Water Please
Hydration seems like a funny word to associate with a hard rock but in the case of opal, it's essential to its staying power. Captured inside its amorphous silica cells is indeed water. Some varieties hold up to 21% hydration by weight.
Note This
Opal should be protected against sudden and extreme temperature changes because of its internal structure.
With opal's delicate Mohs scale ranking of 5.5 to 6 you don't want to bang it around much. Opal bracelets and rings must be worn with care.
What's Precious?
Precious Opal displays the enviable rainbow color effects as light passes through the stone. This is called play-of-color.
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| Rough specimen Precious Opal; Photo Crystalstones.com |
But wait--some opal exhibits none of this razzle dazzle. Now what? This opal variety is made from the same hydrated silica but instead of the multi-color light show, it displays limpid tones of pink, mint, or even pastel blue.
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| Peruvian Blue Opal; Photo Moondrop Creations |
While it's called Common Opal, it's anything but common. Harvested from far away mines located in the Andean mountains of Peru, this sumptuous opal is a connoisseur's dream.
You Like Something Different Don't You?
Interested in collecting some 'out of the ordinary' gemstones for your jewel box? This may be a good place to start.
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