Peterbaylissite is a rare mercury carbonate mineral typically found in the oxidation zones of mercury deposits. It usually forms delicate, transparent, bladed crystals and is a highly sought-after specimen for advanced mineral collectors.
Is this peterbaylissite?
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 peterbaylissite with a known reference. Peterbaylissite sits at Mohs <5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: dark brownish black.
- 3Read the lusterHold the specimen under a strong light. Luster: submetallic to adamantine.
- 4Match the color rangeCompare against the expected color range: black, dark red brown.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: granular.
Often confused with
Peterbaylissite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Peterbaylissite is noticeably harder (Mohs <5 vs. 3); streak differs, so Peterbaylissite leaves dark brownish black, Calcite leaves white; luster reads submetallic to adamantine on Peterbaylissite and vitreous; pearly on cleavages and {0001} on Calcite.
How to tell apart: Peterbaylissite is noticeably harder (Mohs <5 vs. 3.5-4); streak differs, so Peterbaylissite leaves dark brownish black, Aragonite leaves white; luster reads submetallic to adamantine on Peterbaylissite and vitreous, resinous on fracture surfaces on Aragonite.
Often found alongside peterbaylissite
Minerals reported to co-occur with peterbaylissite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Hg₃CO₃(OH)·2H₂O
- Mohs hardness
- <5
- Density
- 7.14 g/cm³
- Colors
- BlackDark red brown
- Streak
- Dark brownish black
- Luster
- Submetallic to adamantine
- Transparency
- Opaque
- Crystal system
- Orthorhombic
- Crystal habit
- Granular
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Very rare in a mercury deposit in silicate–carbonate rock, hydrothermally altered from serpentinite, probably formed as an alteration product of cinnabar
Where rockhounds find peterbaylissite
Classic worldwide localities
- A small prospect pit near the long abandoned Clear Creek mercury mines, New Idria district, San Benito County, California, USA (type locality)
Field-hunting tip
Where it forms: Very rare in a mercury deposit in silicate–carbonate rock, hydrothermally altered from serpentinite, probably formed as an alteration product of cinnabar. If you start seeing ferroan magnesiochromite, ferroan magnesite, cinnabar 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 peterbaylissite?+
Where is peterbaylissite found?+
Is peterbaylissite safe to handle?+
What rocks look like peterbaylissite?+
What minerals are found with peterbaylissite?+
What kind of rock does peterbaylissite form in?+
What is peterbaylissite used for?+
Find peterbaylissite on the map
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