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What are thundereggs? The rare, chalcedony-filled rocks
They look a bit like geodes, but they’re not exactly geodes. There are three types of rock: igneous, metamorphic, and ...
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World's rarest gemstone: What it looks like and its cost
Unique in its kind, the rarest gemstone in the world is called kyawthuite. The unique specimen is currently housed in the Natural History Museum of Los Angeles County. Where it came from and its ...