IMA mineral species

Sturmanite

🪶 Soft, Scratches Easily

Ca₆Fe³⁺₂(SO₄)₂.₅[B(OH)₄](OH)₁₂·25H₂O

Sulfate mineral.

Sturmanite specimen — Sturmanite-Ettringite-38536.jpg · Wikimedia Commons (see file page for author & license)

Properties

⛏ Mohs hardness2.5

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💅🪙🍶🔪💎

Scratches with a fingernail.

Chemical formula	Ca₆Fe³⁺₂(SO₄)₂.₅[B(OH)₄](OH)₁₂·25H₂O
Elements	Ca, Fe, S, O, B, H
Crystal system	Trigonal
Mohs hardness	2.5
Density	—
Streak	—
Color	—
IMA symbol	Strm
Nickel–Strunz class	7.DG.15

“—” means no reliable value in Wikidata yet. Check Mindat for full data.

Care & Handling

🪶 Soft, Scratches Easily Mohs 2.5: softer than a steel knife, so it scratches easily. Store it apart from harder stones.

Learn more

Sturmanite on Mindat.org
Wikipedia article
Wikidata item Q654795 (source of this page's data – you can correct it there)