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, so 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, 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.