Vasilyevite is a very rare mercury oxyhalide mineral known primarily from the Khaidarkan deposit in Kyrgyzstan. It typically occurs as small, resinous to adamantine platy crystals associated with other secondary mercury minerals in oxidized ore zones.
Is this vasilyevite?
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 vasilyevite with a known reference. Vasilyevite sits at Mohs ~3, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: red-brown.
- 3Read the lusterHold the specimen under a strong light. Luster: adamantine to metallic.
- 4Match the color rangeCompare against the expected color range: silvery gray, black, dark reddish black.
- 5Look at form & habitCrystal system: triclinic. Typical habit: microscopic crystals.
Often confused with
Vasilyevite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Vasilyevite leaves red-brown, Eglestonite leaves yellow or greenish yellow, rapidly becoming black; luster reads adamantine to metallic on Vasilyevite and brilliant adamantine to resinous on Eglestonite.
How to tell apart: Streak differs, so Vasilyevite leaves red-brown, Kleinite leaves sulfur-yellow.
Often found alongside vasilyevite
Minerals reported to co-occur with vasilyevite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (Hg₂)₁₀O₆I₃Br₂Cl(CO₃)
- Mohs hardness
- ~3
- Density
- 9.57 g/cm³
- Colors
- Streak
- Red-brown
- Luster
- Adamantine to metallic
- Transparency
- Translucent
- Crystal system
- Triclinic
- Crystal habit
- Microscopic crystals
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- A rare mineral replacing native mercury in vugs in hydrothermal quartz veins
Where rockhounds find vasilyevite
Classic worldwide localities
- Clear Creek mercury mine, New Idria district, San Benito County, California, USA
Field-hunting tip
Where it forms: A rare mineral replacing native mercury in vugs in hydrothermal quartz veins. If you start seeing native mercury, eglestonite, montroydite in float, you are in the right ground. Typical habit: microscopic crystals. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify vasilyevite?+
Where is vasilyevite found?+
Is vasilyevite safe to handle?+
What rocks look like vasilyevite?+
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Find vasilyevite on the map
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