The Tokyo Gem & Mineral show is here and I just had my first go at it. I will do a full write up for Mineral Mondays, but for Friday's Rock! here is one of the gems I picked up. It's a boulder opal with some serious electric blue fire.
While boulder opal often contains blue fire, this one stood out because of the amount of blue and how vivid it is.
Opal is made up of tiny spheres of silica. It is formed when silica rich fluids percolate through rock and deposit into cracks and vugs.
When light hits opal the waves bounce around in between those spheres. Certain wavelengths are blocked until the light finds its way out. Depending on how the closely packed the silica spheres are or how they are layered determines the visible light waves that makes its way out.
So this piece of boulder opal is primarily producing blue light. But it is intense, just like in the photos. It almost looks fake even in real life. There are areas of greens, yellows and reds, but those are small and few and totally overshadowed by the blue.
That's it. Thanks for reading. I'll be back Monday with a Tokyo Gem & Mineral Show report!
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