Kornelite is a rare iron sulfate mineral that typically forms as a result of the oxidation of pyrite and other iron-bearing sulfides. Collectors look for its distinctive acicular or fibrous habit, often found as delicate clusters or crusts within arid mining environments.
Is this kornelite?
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 kornelite with a known reference. Kornelite sits at Mohs 2.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Kornelite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Kornelite typically shows a vitreous to pearly luster.
- 4Match the color rangeCompare against the expected color range: violet, lavender, pinkish-white.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: acicular crystals, fibrous aggregates, crusts.
Often confused with
Kornelite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Luster reads vitreous to pearly on Kornelite and vitreous on Quenstedtite.
How to tell apart: Luster reads vitreous to pearly on Kornelite and vitreous on Coquimbite.
How to tell apart: Streak differs, so Kornelite leaves white, Copiapite leaves yellow; luster reads vitreous to pearly on Kornelite and pearly on Copiapite.
Often found alongside kornelite
Minerals reported to co-occur with kornelite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Fe₂(SO₄)₃·7H₂O
- Mohs hardness
- 2.5
- Density
- 2.32 g/cm³
- Streak
- White
- Luster
- Vitreous to Pearly
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Acicular Crystals, Fibrous Aggregates, Crusts
- Cleavage
- Perfect On {010}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Oxidized Zones of Sulfide Ore Deposits
- Typical price
- $20-150 thumbnail
Where rockhounds find kornelite
Classic worldwide localities
- Kutná Hora, Czech Republic
- Alcaparrosa Mine, Chile
- Chuquicamata, Chile
Field-hunting tip
Look in oxidized zones of sulfide ore deposits country, the host setting where kornelite typically forms. If you start seeing coquimbite, copiapite, jarosite in float, you are in the right ground. Field specimens usually show a acicular crystals, fibrous aggregates, crusts habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find kornelite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
