IMA mineral species
Sewardite
CaFe³⁺₂(AsO₄)₂(OH)₂
Arsenate mineral.
Properties
⛏ Mohs hardness3.5
💅🪙🍶🔪💎
A copper coin scratches it.
⚖ Density4.156 g/cm³
Heavy
| Chemical formula | CaFe³⁺₂(AsO₄)₂(OH)₂ |
|---|---|
| Elements | Ca, Fe, As, O, H |
| Crystal system | — |
| Mohs hardness | 3.5 |
| Density | 4.156 g/cm³ |
| Streak | brown |
| Color | — |
| IMA symbol | Sew |
| Nickel–Strunz class | 8.BH.30 |
“—” means no reliable value in Wikidata yet. Check Mindat for full data.
Care & Handling
- 🪶 Soft, Scratches Easily Mohs 3.5: softer than a steel knife, so it scratches easily. Store it apart from harder stones.
🌍 Where it's found
Type locality (where it was first described): Tsumeb Mine, Namibia
- 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.
Learn more
- Sewardite on Mindat.org
- Wikipedia article
- Wikidata item Q3958552 (source of this page's data – you can correct it there)
IMA mineral species
3–4
RedOrange
Soft, Scratches Easily