Kleinite is a rare mercury-ammonium chloride sulfate mineral that forms distinct, bright yellow hexagonal crystals. It is primarily found in the oxidized zones of mercury deposits, frequently occurring alongside other rare mercury halides.
Is this kleinite?
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 kleinite with a known reference. Kleinite sits at Mohs 3.5 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Kleinite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Kleinite typically shows a adamantine luster.
- 4Match the color rangeCompare against the expected color range: yellow, pale yellow, orange-yellow.
- 5Look at form & habitCrystal system: hexagonal. Typical habit: hexagonal prismatic crystals, often as crusts or globular aggregates.
Often confused with
Kleinite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Kleinite is noticeably harder (Mohs 3.5 vs. 2.5); streak differs — Kleinite leaves white, Eglestonite leaves yellowish-white.
How to tell apart: Streak differs — Kleinite leaves white, Terlinguaite leaves yellow.
Often found alongside kleinite
Minerals reported to co-occur with kleinite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Hg₂N(Cl,SO₄)·nH₂O
- Mohs hardness
- 3.5
- Density
- 8.24 g/cm³
- Streak
- White
- Luster
- Adamantine
- Transparency
- Transparent
- Crystal system
- Hexagonal
- Crystal habit
- Hexagonal Prismatic Crystals, Often as Crusts or Globular Aggregates
- Cleavage
- Perfect On Basal Pinacoid
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Mercury-bearing Hydrothermal Deposits and Oxidized Zones
- Typical price
- $50-500 per specimen depending on size and quality
Where rockhounds find kleinite
Classic worldwide localities
- Terlingua, Texas, USA
- Mont Saint-Hilaire, Quebec, Canada
- Mapimi, Durango, Mexico
Field-hunting tip
Look in mercury-bearing hydrothermal deposits and oxidized zones country — that is the host setting where kleinite typically forms. If you start seeing calomel, cinnabar, terlinguaite in float, you are in the right ground. Field specimens usually show a hexagonal prismatic crystals, often as crusts or globular aggregates habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find kleinite on the map
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