Pure quartz, or “rock crystal” from Brazil. Source: Didier Descouens, CC BY-SA 4.0 Pick up a rock almost anywhere on Earth and chances are pretty good that there’s at least some quartz in it.
Pure quartz crystals have been spotted on Mars for the first time, as well as other gems like opal. Researchers say these crystals, as well as being evidence of past hydrothermal activity ...
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