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 — 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 — that is 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.
