Puninite is a rare sodium copper sulfate that forms emerald-green crusts of irregularly-shaped grains. It occurs in a sublimate around an active fumarole. Associated minerals include tenorite, hematite and anhydrite. It was first described from Glavnaya Tenoritovaya fumarole, Tolbachik volcano, Kamchatka, Russia.
Is this puninite?
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 puninite with a known reference. Puninite sits at Mohs 2-3, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: greenish.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: emerald-green.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: crusts of irregularly-shaped grains.
Often confused with
Puninite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Eudialyte is the harder of the two (Mohs 5-6 vs. 2-3); streak differs, so Puninite leaves greenish, Eudialyte leaves white.
How to tell apart: Streak differs, so Puninite leaves greenish, Lamprophyllite leaves pale yellow, may have an orange tint; luster reads vitreous on Puninite and submetallic on cleavages on Lamprophyllite.
Often found alongside puninite
Minerals reported to co-occur with puninite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Na₂Cu₃O(SO₄)₃
- Mohs hardness
- 2-3
- Density
- 3.298 g/cm³
- Colors
- Streak
- Greenish
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Crusts of irregularly-shaped grains
- Cleavage
- {100}, perfect
- Rarity
- Rare
- Uses
- Collector
- Host rock
- As a sublimate around an active fumarole
Where rockhounds find puninite
Classic worldwide localities
- Glavnaya Tenoritovaya fumarole, Second scoria cone, Northern Breakthrough of the Great Fissure Eruption, Tolbachik volcano, Kamchatka, Russia
Field-hunting tip
Where it forms: As a sublimate around an active fumarole. If you start seeing lammerite-β, tenorite, hematite in float, you are in the right ground. Typical habit: crusts of irregularly-shaped grains. Train your eye for that shape before scanning the outcrop.
Common questions
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Find puninite on the map
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