Crystopedia
IMA mineral species

Ettringite

Ca₆Al₂(SO₄)₃(OH)₁₂·26H₂O

Hydrated calcium sulfo-aluminate.

YellowWhite & Clear

Ettringite specimen
Charlesite-Ettringite-jmix07-166a.jpg · Wikimedia Commons (see file page for author & license)

Properties

🔷 Trigonal✏️ streak white
Chemical formulaCa₆Al₂(SO₄)₃(OH)₁₂·26H₂O
ElementsCa, Al, S, O, H
Crystal systemTrigonal
Mohs hardness—
Density—
Streakwhite
Color—
IMA symbolEtt
Nickel–Strunz class7.DG.15

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

🌍 Where it's found

Type locality (where it was first described): Bellerberg volcano, Germany

  • Type locality
  • Notable source / deposit
  • Country of origin

Marker positions are approximate (region or locality level). Type localities from Wikidata; notable sources curated by Crystopedia.

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