OCEAN JASPER - Madagascar
« back'OCEAN JASPER'
Mahajanga Province, Madagascar
A small but beautiful example of this unusual rock that is now a popular gemstone. It is polished on the upper surface and underneath are sparkling quartz crystals.
Ocean jasper is not a true jasper but an unusual type of rhyolite: a volcanic lava with a high quartz content. In this particular case the quartz has crystallised as the variety of quartz known as chalcedony. Rhyolite also forms other types of rock such as pumice and obsidian.
Ocean jasper is notable for the spherical aggregates of crystals and it is often called orbicular jasper or orbicular rhyolite. A similar type of rhyolite from Mexico is known as leopard skin jasper.
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Size: 6 x 6.5 x 4 centimetres
Weight: 168 grams
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