gemstones

gemstones

opal – The cause of the brilliant play of colors in opal was an enigma until relatively recently. Scanning electron microscope studies show that opals consist of transparent spheres of silica that are tightly packed. The voids or spaces between the spheres contain air or water. The regular arrangement of spheres acts as a diffraction grating, breaking visible white light into separate colors.
Purple Mojave Turquoise
Larimar
Crystals  / American Museum of Natural History
Potted Vegetable Garden Guide
Blue-Lace Agate Geode
Actually, this is a natural glass, not a crystal. This is moldavite, a glass that formed 15 million years ago, probably as the result of a meteorite impact.
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Rhodochrosite
Rheniite
Shattuckite
gems
amethyst