Mineral group · Amphibole group
Hornblende
Ca2(Mg,Fe,Al)5(Al,Si)8O22(OH)2 (series)
Hornblende is the general name for black calcic amphiboles (magnesio-hornblende, ferro-hornblende and others) in granites, diorites and amphibolites; crystals come from Bohemia, the Eifel, Ontario (Bancroft) and Norway. Cleavage at 56° and 124° distinguishes amphiboles from pyroxenes. It is a reference specimen rather than a display mineral.
| Formula | Ca2(Mg,Fe,Al)5(Al,Si)8O22(OH)2 (series) |
|---|---|
| IMA status | group |
| Crystal system | Monoclinic |
| Mohs hardness | 5–6 |
| Group | Amphibole group |
| Type locality | None |
| Streak | Grey-green |
| Specific gravity | 3.2 |
Elsewhere
Cite this article
Stratum Study. "Hornblende" (Mineral). Stratum Study pack 2026.09, as of 2026-09-19. https://stratum.black/study/minerals/hornblende. Accessed 2026-09-20.
@misc{stratum-hornblende,
title = {Hornblende},
author = {{Stratum Study}},
howpublished = {\url{https://stratum.black/study/minerals/hornblende}},
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.