Quartz is a silicon dioxide crystal with a hardness of 7. Its crystal system is hexagonal (trigonal), and it is among the most abundant of minerals. The silicon oxide molecule of Quartz is a part of the wide array of minerals designated as ‘silicates’. Quartz crystals are found on every continent, and perhaps in every country on Earth. The writing in this section is mainly about varieties of Clear Quartz crystals, except as otherwise noted.
Classically, Clear Quartz stones are thought of as colourless, candle-shaped hexagonal prismatic crystals with relatively smooth sides and naturally facetted terminations at one or both ends.