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.

Hardness

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent

mineralrare

Peterbaylissite

Hardness: 2
Luster: Vitreous
Streak: White
Transparency: Transparent

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Is this peterbaylissite?

5-step field check

Run through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.

1
Test the hardness
Try to scratch peterbaylissite with a known reference. Peterbaylissite sits at Mohs 2 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Peterbaylissite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Peterbaylissite typically shows a vitreous luster.
4
Match the color range
Compare against the expected color range: colorless, white.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: bladed crystals.

Often confused with

Peterbaylissite vs. its common look-alikes — and how to tell them apart in the field.

mineral

Calcite

Mohs 3

How to tell apart: Calcite is the harder of the two (Mohs 3 vs. 2).

How to tell apart: Aragonite is the harder of the two (Mohs 3.5-4 vs. 2).

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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)₂
Mohs hardness: 2
Density: 3.55 g/cm³
Colors: Colorless White
Streak: White
Luster: Vitreous
Transparency: Transparent
Crystal system: Monoclinic
Crystal habit: Bladed Crystals
Cleavage: Perfect On {010}
Rarity: Rare
Uses: Collector
Host rock: Mercury-rich Hydrothermal Deposits
Typical price: $50-300+ per specimen

Where rockhounds find peterbaylissite

Classic worldwide localities

Almaden Mine, Spain
Terlingua District, Texas, USA

Field-hunting tip

Look in mercury-rich hydrothermal deposits country — that is the host setting where peterbaylissite typically forms. If you start seeing cinnabar, calomel, terlinguaite in float, you are in the right ground. Field specimens usually show a bladed crystals habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify peterbaylissite?+

Mohs hardness is 2. It typically shows a vitreous luster. The streak is white. Common colors include colorless, white.

Where is peterbaylissite found?+

Notable localities include Almaden Mine, Spain; Terlingua District, Texas, USA.

How much is peterbaylissite worth?+

Typical asking prices fall in the range of $50-300+ per specimen. Quality, size, and provenance can move individual specimens well outside that range.

Is peterbaylissite safe to handle?+

It contains toxic constituents. Contains mercury; handle with caution, avoid ingestion, inhalation of dust, or skin contact. Wash hands thoroughly after handling. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like peterbaylissite?+

Peterbaylissite is most often confused with Calcite, Aragonite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with peterbaylissite?+

Peterbaylissite commonly co-occurs with Cinnabar, Calomel, Terlinguaite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does peterbaylissite form in?+

Peterbaylissite typically forms in mercury-rich hydrothermal deposits. Working float back to the host body is the standard way to chase a fresh occurrence.

What is peterbaylissite used for?+

Peterbaylissite is used in collector.

Find peterbaylissite on the map

RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.