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, so Metahohmannite leaves yellow, Hohmannite leaves yellowish orange.
How to tell apart: Streak differs, so Metahohmannite leaves yellow, Amarantite leaves yellowish-orange.
How to tell apart: Streak differs, so 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, 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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