Clear quartz, also called rock crystal, is quartz in its purest form: silicon dioxide with barely any impurities. The ancient Greeks believed it was ice frozen so deeply it could never melt, which is where the word crystal comes from. It is one of the most abundant minerals on Earth, found on every continent, with famous sources in Brazil, Madagascar, the Alps and Arkansas in the USA. Before glass was perfected, rock crystal was carved into everything from goblets to chandelier drops.
With a hardness of 7 and no cleavage, clear quartz is a workhorse: fine for daily rings, bracelets and anything else. It is faceted, carved, tumbled and cut into beads, and flawless material has a lovely icy sparkle. Its main look-alike is plain glass, which is softer, often contains round bubbles, and feels warmer to the touch. Lab-grown quartz also exists and should be labelled as such. Care is as simple as it gets: warm, soapy water and a soft cloth.
All quartz varieties. Rutilated and phantom quartz are clear quartz with beautiful natural inclusions.
