Mineral · Quartz group
Quartz
SiO2
Quartz is silicon dioxide, the most abundant mineral collectors own and the parent of amethyst, citrine, smoky quartz, rose quartz, agate and chalcedony. Clear rock-crystal points and clusters from Arkansas, Brazil, Madagascar and the Alps are the entry to mineral collecting; hardness 7, conchoidal fracture and six-sided prisms with striations across the faces identify it. Glass imitations are softer and show bubbles.
| Formula | SiO2 |
|---|---|
| IMA status | grandfathered |
| Crystal system | Trigonal |
| Mohs hardness | 7 |
| Group | Quartz group |
| Type locality | None (known since antiquity) |
| Streak | White |
| Specific gravity | 2.65 |
| Reference list | IMA List of Minerals (RRUFF) — verify formula and status against the current list |
Fakes and treatments
'Aura' quartz (angel, titanium, rainbow) is vapour-coated with metal; sold honestly it is a treated stone, not a mineral variety. Arkansas clusters are routinely acid-cleaned of iron staining, which is accepted; glued-on points are not.
Elsewhere
Cite this article
Stratum Strata. "Quartz" (Mineral). Stratum Strata pack 2026.09, as of 2026-09-21. https://stratum.black/strata/minerals/quartz. Accessed 2026-09-21.
@misc{stratum-quartz,
title = {Quartz},
author = {{Stratum Strata}},
howpublished = {\url{https://stratum.black/strata/minerals/quartz}},
year = {2026},
note = {Mineral article, Stratum Strata pack 2026.09, as of 2026-09-21; sources: stratum, wikidata, commons. Accessed 2026-09-21.}
} Citations carry the pack version and the article's as-of date so they resolve to the same text later. The facts themselves belong to the sources listed below; cite those for the science.