Hydrohonessite is a rare nickel-iron sulfate hydroxide mineral typically found as a secondary weathering product in nickel-sulfide ore deposits. It usually appears as fine-grained, yellow, platy crusts or coatings and is structurally related to the pyroaurite-sjögrenite group.
Is this hydrohonessite?
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 hydrohonessite with a known reference. Hydrohonessite sits at Mohs 1-2, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: yellow white.
- 3Read the lusterHold the specimen under a strong light. Luster: adamantine.
- 4Match the color rangeCompare against the expected color range: yellow, bright yellow.
- 5Look at form & habitCrystal system: hexagonal. Typical habit: hexagonal, platy, thin.
Often confused with
Hydrohonessite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Hydrohonessite leaves yellow white, Honessite leaves brownish white; luster reads adamantine on Hydrohonessite and earthy on Honessite.
How to tell apart: Gaspéite is the harder of the two (Mohs 4.5-5 vs. 1-2); streak differs, so Hydrohonessite leaves yellow white, Gaspéite leaves yellow-green; luster reads adamantine on Hydrohonessite and vitreous to dull on Gaspéite.
Often found alongside hydrohonessite
Minerals reported to co-occur with hydrohonessite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ni₆Fe³⁺₂SO₄(OH)₁₆·7H₂O
- Mohs hardness
- 1-2
- Density
- 2.635 g/cm³
- Colors
- Streak
- Yellow white
- Luster
- Adamantine
- Transparency
- Transparent to translucent
- Crystal system
- Hexagonal
- Crystal habit
- Hexagonal, platy, thin
- Cleavage
- Perfect basal
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Incrusting fractures in the oxidized portions of Ni–Fe sulfide deposits (Otter Shoot mine and Carr Boyd mine, Australia); or in chromitite (Unst, Scotland; Linden, Wisconsin, USA)
Where rockhounds find hydrohonessite
Classic worldwide localities
- Linden, Iowa Co., Wisconsin, USA
- A prospect 13 km east-southeast of Gray Mountain, Cameron district, Coconino Co., Arizona, USA
- Otter Shoot nickel mine, Kambalda, 56 km south of Kalgoorlie, Australia
- Carr Boyd Rocks nickel mine, Yerilla district, 80 km north-northeast of Kalgoorlie, Australia
- Hagdale quarry, Unst, Shetland Islands, Scotland
Field-hunting tip
Where it forms: Incrusting fractures in the oxidized portions of Ni–Fe sulfide deposits (Otter Shoot mine and Carr Boyd mine, Australia); or in chromitite (Unst, Scotland; Linden, Wisconsin, USA). If you start seeing honessite, reevesite, magnesite in float, you are in the right ground. Typical habit: hexagonal, platy, thin. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify hydrohonessite?+
Where is hydrohonessite found?+
Is hydrohonessite safe to handle?+
What rocks look like hydrohonessite?+
What minerals are found with hydrohonessite?+
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Find hydrohonessite on the map
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