Pure quartz, or “rock crystal” from Brazil ... in the crystal matrix and turn it gray (smoky quartz). Natural quartz crystals usually have a long body with a hexagonal cross-section with ...

Unlike mineral particles found in clouds on Earth, the quartz crystals detected in the clouds of WASP-17 b are not swept up from a rocky surface. Instead, they originate in the atmosphere itself.

Large crystals found in geodes and other rocks are relatively ... and form natural resources such as gold, tin, iron, marble, and granite. Silicates—including quartz, mica, olivine, and precious ...

Geodes, for instance, are created when mineral-rich water seeps into hollow spaces within rock formations and slowly evaporates, leaving behind dazzling crystals like quartz and amethyst.