Metahohmannite is a rare hydrated iron sulfate that typically forms in the arid, oxidized zones of pyrite-rich mineral deposits. It is often found as a dehydration product of hohmannite, manifesting as small, yellow, translucent crystals or crusts that are easily overlooked by general collectors.
Is this metahohmannite?
5-step field checkRun through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.
- 1Test the hardnessTry to scratch metahohmannite with a known reference. Metahohmannite sits at Mohs 2.5-3 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Metahohmannite leaves a yellow streak.
- 3Read the lusterHold the specimen under a strong light. Metahohmannite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: yellow, brownish-yellow.
- 5Look at form & habitCrystal system: triclinic. Typical habit: tabular to prismatic crystals, crusts.
Often confused with
Metahohmannite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Streak differs — Metahohmannite leaves yellow, Hohmannite leaves yellowish orange.
How to tell apart: Streak differs — Metahohmannite leaves yellow, Amarantite leaves yellowish-orange.
How to tell apart: Streak differs — Metahohmannite leaves yellow, Coquimbite leaves white.
Often found alongside metahohmannite
Minerals reported to co-occur with metahohmannite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Fe³⁺₂(SO₄)₂(OH)₂·4H₂O
- Mohs hardness
- 2.5-3
- Density
- 2.75-2.85 g/cm³
- Colors
- Streak
- Yellow
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Triclinic
- Crystal habit
- Tabular to Prismatic Crystals, Crusts
- Cleavage
- None Observed
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Oxidized Zones of Sulfide Ore Deposits
- Typical price
- $20-150 thumbnail specimens
Where rockhounds find metahohmannite
Classic worldwide localities
- Chuquicamata, Chile
- Alcaparrosa mine, Chile
- Quetena mine, Chile
Field-hunting tip
Look in oxidized zones of sulfide ore deposits country — that is the host setting where metahohmannite typically forms. If you start seeing hohmannite, copiapite, amarantite in float, you are in the right ground. Field specimens usually show a tabular to prismatic crystals, crusts habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find metahohmannite on the map
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