Mineral · Feldspar group
Labradorite
(Ca,Na)(Al,Si)4O8
Labradorite is the calcic plagioclase feldspar famous for labradorescence, the blue, gold and green schiller from lamellar twinning, sold as polished slabs and tumbled stones from Madagascar and as spectrolite from Finland; Labrador's Paul Island is the type locality. Polished Madagascan labradorite is cheap; Finnish spectrolite and 'rainbow moonstone' (a white labradorite from India) cost more. Rotate the stone to see the flash.
| Formula | (Ca,Na)(Al,Si)4O8 |
|---|---|
| IMA status | approved |
| Crystal system | Triclinic |
| Mohs hardness | 6–6.5 |
| Group | Feldspar group |
| Type locality | Paul Island, Labrador, Canada |
| Streak | White |
| Specific gravity | 2.7 |
| Reference list | IMA List of Minerals (RRUFF) — verify formula and status against the current list |
Elsewhere
Cite this article
Stratum Study. "Labradorite" (Mineral). Stratum Study pack 2026.09, as of 2026-09-19. https://stratum.black/study/minerals/labradorite. Accessed 2026-09-20.
@misc{stratum-labradorite,
title = {Labradorite},
author = {{Stratum Study}},
howpublished = {\url{https://stratum.black/study/minerals/labradorite}},
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.