Wattersite is a rare mercury-chromium mineral characterized by its vibrant red color and high density. It is typically found in mercury-rich hydrothermal deposits within serpentinized rocks, appearing as small, distinct tabular crystals.

Hardness

Mohs

Luster

Adamantine

Streak

Yellowish-orange

Transparency

Translucent

mineralrare

Wattersite

Hardness: 3
Luster: Adamantine
Streak: Yellowish-orange
Transparency: Translucent

Is this wattersite?

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 wattersite with a known reference. Wattersite sits at Mohs 3 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Wattersite leaves a yellowish-orange streak.
3
Read the luster
Hold the specimen under a strong light. Wattersite typically shows a adamantine luster.
4
Match the color range
Compare against the expected color range: red.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: tabular crystals.

Often confused with

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

mineral

Cinnabar

Mohs 2-2.5

How to tell apart: Streak differs — Wattersite leaves yellowish-orange, Cinnabar leaves scarlet.

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Often found alongside wattersite

Minerals reported to co-occur with wattersite. Spotting these in float or country rock is a strong cue you are in the right ground.

All properties

Chemical formula: Hg³⁺₄Hg²⁺CrO₆
Mohs hardness: 3
Density: 8.35 g/cm³
Colors: Red
Streak: Yellowish-orange
Luster: Adamantine
Transparency: Translucent
Crystal system: Monoclinic
Crystal habit: Tabular Crystals
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: Serpentinite
Typical price: $100-500 for small thumbnail specimens

Where rockhounds find wattersite

Classic worldwide localities

Clear Creek District, San Benito County, California, USA

Field-hunting tip

Look in serpentinite country — that is the host setting where wattersite typically forms. If you start seeing cinnabar, calomel, eglestonite in float, you are in the right ground. Field specimens usually show a tabular crystals habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify wattersite?+

Mohs hardness is 3. It typically shows a adamantine luster. The streak is yellowish-orange. Common colors include red.

Where is wattersite found?+

Notable localities include Clear Creek District, San Benito County, California, USA.

How much is wattersite worth?+

Typical asking prices fall in the range of $100-500 for small thumbnail specimens. Quality, size, and provenance can move individual specimens well outside that range.

Is wattersite safe to handle?+

It contains toxic constituents. Contains mercury and chromium; toxic if ingested, inhaled as dust, or handled excessively. Wash hands thoroughly after handling and keep in a sealed container. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like wattersite?+

Wattersite is most often confused with Cinnabar. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with wattersite?+

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

What kind of rock does wattersite form in?+

Wattersite typically forms in serpentinite. Working float back to the host body is the standard way to chase a fresh occurrence.

What is wattersite used for?+

Wattersite is used in collector.

Find wattersite on the map

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