Deanesmithite is a rare mercury-chromium sulfide-chromate mineral found primarily in the mercury mines of California. It is highly prized by collectors for its brilliant red color and its association with other rare mercury minerals in hydrothermal vein systems.
Is this deanesmithite?
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 deanesmithite with a known reference. Deanesmithite 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. Deanesmithite leaves a orange-red streak.
- 3Read the lusterHold the specimen under a strong light. Deanesmithite typically shows a adamantine luster.
- 4Match the color rangeCompare against the expected color range: bright red, orange-red.
- 5Look at form & habitCrystal system: trigonal. Typical habit: tabular to blocky crystals, often as crusts.
Often confused with
Deanesmithite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside deanesmithite
Minerals reported to co-occur with deanesmithite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Hg⁺₁₂Hg²⁺₃(CrO₄)S₅
- Mohs hardness
- 2.5
- Density
- 8.5 g/cm³
- Colors
- Streak
- Orange-red
- Luster
- Adamantine
- Transparency
- Translucent
- Crystal system
- Trigonal
- Crystal habit
- Tabular to Blocky Crystals, Often as Crusts
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Hydrothermal Mercury Deposits
- Typical price
- $100-500 per specimen
Where rockhounds find deanesmithite
Classic worldwide localities
- Clear Creek mine, California, USA
Field-hunting tip
Look in hydrothermal mercury deposits country — that is the host setting where deanesmithite typically forms. If you start seeing cinnabar, eglestonite, calomel in float, you are in the right ground. Field specimens usually show a tabular to blocky crystals, often as crusts habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find deanesmithite on the map
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