Kuznetsovite is a rare mercury-arsenic oxychloride mineral that typically forms small, distinct tetrahedral crystals. It is primarily found in the unique hydrothermal environment of the Khaidarkan mercury-antimony deposit. Due to its toxic mercury and arsenic content and extreme rarity, it is sought after primarily by advanced mineral collectors.

Hardness

3.5

Mohs

Luster

Adamantine

Streak

Yellow-orange

Transparency

Translucent

mineralrare

Kuznetsovite

Hardness: 3.5
Luster: Adamantine
Streak: Yellow-orange
Transparency: Translucent

Is this kuznetsovite?

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 kuznetsovite with a known reference. Kuznetsovite sits at Mohs 3.5 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Kuznetsovite leaves a yellow-orange streak.
3
Read the luster
Hold the specimen under a strong light. Kuznetsovite typically shows a adamantine luster.
4
Match the color range
Compare against the expected color range: dark red, red-brown, orange-red.
5
Look at form & habit
Crystal system: cubic. Typical habit: tetrahedral crystals, massive.

Often confused with

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

mineral

Cinnabar

Mohs 2-2.5

How to tell apart: Kuznetsovite is noticeably harder (Mohs 3.5 vs. 2-2.5); streak differs — Kuznetsovite leaves yellow-orange, Cinnabar leaves scarlet.

How to tell apart: Streak differs — Kuznetsovite leaves yellow-orange, Kleinite leaves white.

Compare →

Often found alongside kuznetsovite

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

All properties

Chemical formula: Hg₃AsO₄Cl
Mohs hardness: 3.5
Density: 6.8 g/cm³
Colors: Dark Red Red-brown Orange-red
Streak: Yellow-orange
Luster: Adamantine
Transparency: Translucent
Crystal system: Cubic
Crystal habit: Tetrahedral Crystals, Massive
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: Mercury-antimony Hydrothermal Deposits
Typical price: $100-500 thumbnail

Where rockhounds find kuznetsovite

Classic worldwide localities

Khaidarkan antimony-mercury deposit, Kyrgyzstan

Field-hunting tip

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

Common questions

How do you identify kuznetsovite?+

Mohs hardness is 3.5. It typically shows a adamantine luster. The streak is yellow-orange. Common colors include dark red, red-brown, orange-red.

Where is kuznetsovite found?+

Notable localities include Khaidarkan antimony-mercury deposit, Kyrgyzstan.

How much is kuznetsovite worth?+

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

Is kuznetsovite safe to handle?+

It contains toxic constituents. Contains mercury and arsenic. Handle with care, avoid creating dust, wash hands thoroughly after handling, and store in a sealed container. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like kuznetsovite?+

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

What minerals are found with kuznetsovite?+

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

What kind of rock does kuznetsovite form in?+

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

What is kuznetsovite used for?+

Kuznetsovite is used in collector.

Find kuznetsovite on the map

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