Aurivilliusite is a rare mercury oxyhalide mineral often found as small, yellow, tabular crystals or coatings. It is primarily identified by its extreme density and association with other secondary mercury minerals in oxidation zones of mercury deposits.

Hardness

Mohs

Luster

Adamantine

Streak

Yellow

Transparency

Translucent

mineralrare

Aurivilliusite

Hardness: 2
Luster: Adamantine
Streak: Yellow
Transparency: Translucent

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Is this aurivilliusite?

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 aurivilliusite with a known reference. Aurivilliusite 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. Aurivilliusite leaves a yellow streak.
3
Read the luster
Hold the specimen under a strong light. Aurivilliusite typically shows a adamantine luster.
4
Match the color range
Compare against the expected color range: yellow, brownish-yellow.
5
Look at form & habit
Crystal system: tetragonal. Typical habit: tabular crystals, crusts.

Often confused with

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

mineral

Eglestonite

Mohs 2.5

How to tell apart: Streak differs — Aurivilliusite leaves yellow, Eglestonite leaves yellowish-white.

Often found alongside aurivilliusite

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

All properties

Chemical formula: Hg₄O₂ClI
Mohs hardness: 2
Density: 8.85 g/cm³
Colors: Yellow Brownish-yellow
Streak: Yellow
Luster: Adamantine
Transparency: Translucent
Crystal system: Tetragonal
Crystal habit: Tabular Crystals, Crusts
Cleavage: Perfect
Rarity: Rare
Uses: Collector
Host rock: Mercury-rich Hydrothermal Deposits
Typical price: $200-1500 per specimen

Where rockhounds find aurivilliusite

Classic worldwide localities

Krutaya Gorka, Russia
Terlingua District, USA

Field-hunting tip

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

Common questions

How do you identify aurivilliusite?+

Mohs hardness is 2. It typically shows a adamantine luster. The streak is yellow. Common colors include yellow, brownish-yellow.

Where is aurivilliusite found?+

Notable localities include Krutaya Gorka, Russia; Terlingua District, USA.

How much is aurivilliusite worth?+

Typical asking prices fall in the range of $200-1500 per specimen. Quality, size, and provenance can move individual specimens well outside that range.

Is aurivilliusite safe to handle?+

It contains toxic constituents. Contains mercury and iodine; handle with care and wash hands thoroughly after contact. Do not inhale dust or allow to come into contact with mucous membranes. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like aurivilliusite?+

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

What minerals are found with aurivilliusite?+

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

What kind of rock does aurivilliusite form in?+

Aurivilliusite 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 aurivilliusite used for?+

Aurivilliusite is used in collector.

Find aurivilliusite on the map

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