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.

Right: OH-defects in young (0.3 Gyr) Variscan granites are one order of magnitude higher than in old (0.9-1.8 Gyr) Proterozoic granites from Scandinavia . The OH-content is reflected in recent ...

Evidence for the use of rock crystal - a rare type of perfectly transparent quartz which forms in large hexagonal gems - has occasionally been found at prehistoric sites in the British Isles, but ...

More than 4,000 naturally occurring minerals—inorganic solids that have a characteristic chemical composition and specific crystal structure ... formed when molten rock, or magma, cools ...