Free-form Mexican jelly opal, snowbowl chalcedony Measures 25mm x 30mm on a wire drop [trigger heading="Why Is This Unique?" text="Mexican Opal was prized and used for jewelry, mosaics, and sculpture of the Mayas and Aztecs. Known to the Aztecs by the name Vitzitziltecpa, which means hummingbird stone due to its similarity to the bright iridescent colors of the bird’s plumage. Formed in the depths of ancient volcanoes, jelly opal was created when water seeps into silica-rich lava, filling its seams and hollows. Under this incredible heat and pressure, the lava traps water within itself, forming into opal in pockets and thin openings in the rock. Mexican opal comes in two types: 1) Fire opal which is a term now reserved for orange to red opal, with or without play of color and 2) Jelly opal which is a cloudy or translucent opal with a jelly-like appearance, sometimes with a blueish tint to it. Fire opal is unique in that it has vivid color while remaining highly transparent, and while both types of opals generally lack play of color, those specimens which possess it are very rare and valuable. The larger and more clear the stone, the more rare."]