Grechishchevite is a rare mercury sulfohalide mineral found primarily in specific Russian mercury deposits. It typically forms small, reddish-brown crystals that are prized by advanced mineral collectors for their unique composition and scarcity.
Is this grechishchevite?
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 grechishchevite with a known reference. Grechishchevite 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. Streak: deep yellow to yellow with slight orange tint.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous to adamantine.
- 4Match the color rangeCompare against the expected color range: brownish black, orange, reddish orange.
- 5Look at form & habitCrystal system: tetragonal. Typical habit: microscopic crystals, prismatic.
Often confused with
Grechishchevite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Grechishchevite leaves deep yellow to yellow with slight orange tint, Cinnabar leaves scarlet; luster reads vitreous to adamantine on Grechishchevite and adamantine, inclining to metallic when dark; dull in friable material on Cinnabar.
How to tell apart: Streak differs, so Grechishchevite leaves deep yellow to yellow with slight orange tint, Lavrentievite leaves white.
Often found alongside grechishchevite
Minerals reported to co-occur with grechishchevite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Hg₃S₂BrCl₀.₅I₀.₅
- Mohs hardness
- ~2.5
- Density
- 7.23 g/cm³
- Streak
- Deep yellow to yellow with slight orange tint
- Luster
- Vitreous to adamantine
- Transparency
- Transparent
- Crystal system
- Tetragonal
- Crystal habit
- Microscopic crystals, prismatic
- Cleavage
- Good
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In hydrothermal mercury deposits
Where rockhounds find grechishchevite
Classic worldwide localities
- Arzak and Kadyrel deposits, Tuva, Siberia, Russia
Field-hunting tip
Where it forms: In hydrothermal mercury deposits. If you start seeing cinnabar, calomel, kuzminite in float, you are in the right ground. Typical habit: microscopic crystals, prismatic. Train your eye for that shape before scanning the outcrop.
Common questions
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What rocks look like grechishchevite?+
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Find grechishchevite on the map
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