Mineral · Tourmaline group
Schorl
NaFe2+3Al6(Si6O18)(BO3)3(OH)3(OH)
Schorl is black iron tourmaline, the commonest tourmaline, forming striated prisms in granite pegmatites worldwide and the black needles in quartz ('tourmalinated quartz'). Erongo (Namibia) and Brazil produce lustrous terminated crystals at low prices. It is sold in bulk as 'black tourmaline' for metaphysical use.
| Formula | NaFe2+3Al6(Si6O18)(BO3)3(OH)3(OH) |
|---|---|
| IMA status | approved |
| Crystal system | Trigonal |
| Mohs hardness | 7 |
| Group | Tourmaline group |
| Type locality | Zschorlau, Saxony, Germany |
| Streak | White |
| Specific gravity | 3.2 |
| Reference list | IMA List of Minerals (RRUFF) — verify formula and status against the current list |
Elsewhere
Cite this article
Stratum Study. "Schorl" (Mineral). Stratum Study pack 2026.09, as of 2026-09-19. https://stratum.black/study/minerals/schorl. Accessed 2026-09-20.
@misc{stratum-schorl,
title = {Schorl},
author = {{Stratum Study}},
howpublished = {\url{https://stratum.black/study/minerals/schorl}},
year = {2026},
note = {Mineral article, Stratum Study pack 2026.09, as of 2026-09-19; sources: stratum, wikidata, commons. Accessed 2026-09-20.}
} 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.