Kuzminite is an extremely rare mercury halide mineral typically found as fine-grained aggregates in mercury-rich hydrothermal deposits. Due to its chemical composition, it is sensitive to light and should be stored in a dark environment to prevent degradation.
Is this kuzminite?
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 kuzminite with a known reference. Kuzminite 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. Kuzminite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Kuzminite typically shows a greasy luster.
- 4Match the color rangeCompare against the expected color range: white, gray.
- 5Look at form & habitCrystal system: tetragonal. Typical habit: granular.
Often confused with
Kuzminite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Luster reads greasy on Kuzminite and adamantine on Calomel.
How to tell apart: Streak differs — Kuzminite leaves white, Eglestonite leaves yellowish-white; luster reads greasy on Kuzminite and adamantine on Eglestonite.
Often found alongside kuzminite
Minerals reported to co-occur with kuzminite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Hg₂ClBr
- Mohs hardness
- 2.5
- Density
- 5.68 g/cm³
- Streak
- White
- Luster
- Greasy
- Transparency
- Opaque
- Crystal system
- Tetragonal
- Crystal habit
- Granular
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Hydrothermal Mercury Deposits
- Typical price
- $100-500+ for micro-specimens
Where rockhounds find kuzminite
Classic worldwide localities
- Kadyrel mercury deposit, Tuva Republic, Russia
Field-hunting tip
Look in hydrothermal mercury deposits country — that is the host setting where kuzminite typically forms. If you start seeing calomel, cinnabar, mercury in float, you are in the right ground. Field specimens usually show a granular habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find kuzminite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
