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, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: white to gray.
- 3Read the lusterHold the specimen under a strong light. Luster: adamantine.
- 4Match the color rangeCompare against the expected color range: white, bluish gray, colorless.
- 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: Streak differs, so Kuzminite leaves white to gray, Calomel leaves pale yellowish white.
How to tell apart: Streak differs, so Kuzminite leaves white to gray, Eglestonite leaves yellow or greenish yellow, rapidly becoming black; luster reads adamantine on Kuzminite and brilliant adamantine to resinous 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
- HgBr
- Mohs hardness
- 2
- Density
- 7-7.2 g/cm³
- Streak
- White to gray
- Luster
- Adamantine
- Transparency
- Transparent
- Crystal system
- Tetragonal
- Crystal habit
- Granular
- Cleavage
- {100}, good
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In vugs in mercury sulfides, in calcite veins in a mercury ore deposit (Kadyrel deposit, Russia)
Where rockhounds find kuzminite
Classic worldwide localities
- Kadyrel mercury deposit, Pii-Khem district, Tuva, Siberia, Russia
- Landsberg, near Obermoschel, Rhineland-Palatinate, Germany
Field-hunting tip
Where it forms: In vugs in mercury sulfides, in calcite veins in a mercury ore deposit (Kadyrel deposit, Russia). If you start seeing eglestonite, lavrentievite, kadyrelite in float, you are in the right ground. Typical habit: granular. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify kuzminite?+
Where is kuzminite found?+
Is kuzminite safe to handle?+
What rocks look like kuzminite?+
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Find kuzminite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
