Honessite is a rare secondary nickel mineral typically found as thin, green to brown coatings or delicate, radiating crusts in the oxidized zones of ore deposits. It is most frequently encountered by collectors associated with millerite in localities like the Wisconsin lead-zinc districts. Due to its softness and delicate habit, it requires careful handling.
Is this honessite?
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 honessite with a known reference. Honessite sits at Mohs 1-1.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: brownish white.
- 3Read the lusterHold the specimen under a strong light. Luster: earthy.
- 4Match the color rangeCompare against the expected color range: green, brown, greenish yellow, yellow.
- 5Look at form & habitCrystal system: hexagonal. Typical habit: massive.
Often confused with
Honessite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Honessite leaves brownish white, Morenosite leaves pale green to white; luster reads earthy on Honessite and vitreous on Morenosite.
How to tell apart: Retgersite is the harder of the two (Mohs 2.5 vs. 1-1.5); streak differs, so Honessite leaves brownish white, Retgersite leaves pale green; luster reads earthy on Honessite and vitreous on Retgersite.
How to tell apart: Streak differs, so Honessite leaves brownish white, Nickelhexahydrite leaves white; luster reads earthy on Honessite and vitreous on Nickelhexahydrite.
Often found alongside honessite
Minerals reported to co-occur with honessite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (Ni₁-xFex)(SO₄)x/2(OH)₂·nH₂O (x < 0.5, n < 3x/2)
- Mohs hardness
- 1-1.5
- Density
- 2.28 g/cm³
- Streak
- Brownish white
- Luster
- Earthy
- Transparency
- Semitransparent
- Crystal system
- Hexagonal
- Crystal habit
- Massive
- Cleavage
- Perfect
- Rarity
- Rare
- Uses
- Collector
- Host rock
- A rare oxidation product of nickel sulfide minerals
Where rockhounds find honessite
Classic worldwide localities
- Linden Pb–Zn deposit, near Linden, Iowa Co., and at Hall’s Gap, Lincoln Co., Wisconsin, USA
- Kamariza mine, Laurium, Greece
- Hagdale quarry, Unst, Shetland Islands, Scotland
Field-hunting tip
Where it forms: A rare oxidation product of nickel sulfide minerals. If you start seeing millerite, violarite, bravoite in float, you are in the right ground. Typical habit: massive. Train your eye for that shape before scanning the outcrop.
Common questions
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Find honessite on the map
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