Clearcreekite is a rare mercury carbonate mineral typically found in mercury-rich deposits. It usually occurs as delicate, transparent crystals associated with cinnabar in hydrothermal environments.
Is this clearcreekite?
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 clearcreekite with a known reference. Clearcreekite sits at Mohs 2-3, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: pale greenish yellow.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: pale greenish yellow.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: subhedral crystals, tabular.
Often confused with
Clearcreekite vs. its common look-alikes, and how to tell them apart in the field.

How to tell apart: Streak differs, so Clearcreekite leaves pale greenish yellow, Calcite leaves white.

How to tell apart: Streak differs, so Clearcreekite leaves pale greenish yellow, Cinnabar leaves scarlet; luster reads vitreous on Clearcreekite and adamantine, inclining to metallic when dark; dull in friable material on Cinnabar.
Often found alongside clearcreekite
Minerals reported to co-occur with clearcreekite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Hg¹⁺₃(CO₃)(OH)·2H₂O
- Mohs hardness
- 2-3
- Density
- 6.96 g/cm³
- Colors
- Streak
- Pale greenish yellow
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Subhedral crystals, tabular
- Cleavage
- Good on {001}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Very rare, probably formed as an alteration product of cinnabar
Where rockhounds find clearcreekite
Classic worldwide localities
- Clear Creek claim, near the Clear Creek mercury mine, New Idria district, San Benito Co., California, USA
Field-hunting tip
Where it forms: Very rare, probably formed as an alteration product of cinnabar. If you start seeing edoylerite, cinnabar in float, you are in the right ground. Typical habit: subhedral crystals, tabular. Train your eye for that shape before scanning the outcrop.

