Retgersite is a rare nickel sulfate mineral typically formed as an alteration product in oxidized nickel deposits. It occurs as delicate, bright green efflorescences or crusts that are extremely sensitive to humidity and can dehydrate if stored improperly.
Is this retgersite?
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 retgersite with a known reference. Retgersite 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. Streak: pale green.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: dark green.
- 5Look at form & habitCrystal system: tetragonal. Typical habit: crusts, granular, acicular or fibrous aggregates.
Often confused with
Retgersite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside retgersite
Minerals reported to co-occur with retgersite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- NiSO₄·6H₂O
- Mohs hardness
- 2.5
- Density
- 2.04 g/cm³
- Colors
- Streak
- Pale green
- Luster
- Vitreous
- Transparency
- Semitransparent
- Crystal system
- Tetragonal
- Crystal habit
- Crusts, granular, acicular or fibrous aggregates
- Cleavage
- On {001}, perfect; on {110}, in traces, microscopically observed
- Rarity
- Rare
- Uses
- Collector
- Host rock
- An uncommon secondary mineral in the oxidization zone of nickel-bearing hydrothermal mineral deposits, formed from H2O solution between 31.5°C and 53.5°C
Where rockhounds find retgersite
Classic worldwide localities
- Cottonwood Canyon, at the Nickel and Lovelock mines, Table Mountain district, Churchill Co., Nevada, USA
- Gap Nickel mine, Lancaster Co., Pennsylvania, USA
- Mine La Motte, Fredericktown, Madison Co., Missouri, USA
- Minasragra, 46 km from Cerro de Pasco, Peru
- Key Lake, Saskatchewan, Canada
- Lichtenberg, near Bayreuth, Bavaria, Germany
Field-hunting tip
Where it forms: An uncommon secondary mineral in the oxidization zone of nickel-bearing hydrothermal mineral deposits, formed from H2O solution between 31.5°C and 53.5°C. If you start seeing nickeline, gersdorffite, nickelian pyrite in float, you are in the right ground. Typical habit: crusts, granular, acicular or fibrous aggregates. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify retgersite?+
Where is retgersite found?+
Is retgersite safe to handle?+
What rocks look like retgersite?+
What minerals are found with retgersite?+
What kind of rock does retgersite form in?+
What is retgersite used for?+
Find retgersite on the map
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