Barquillite is a very rare copper mercury germanium sulfide mineral known primarily from the Bor Pit in Russia. It typically appears as dark, metallic tabular crystals or massive grains within complex sulfide-rich hydrothermal deposits.

Hardness

2.5-3

Mohs

Luster

Metallic

Streak

Grey-black

Transparency

Opaque

mineralrare

Barquillite

Hardness: 2.5-3
Luster: Metallic
Streak: Grey-black
Transparency: Opaque

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Is this barquillite?

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 barquillite with a known reference. Barquillite sits at Mohs 2.5-3, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Barquillite leaves a grey-black streak.
3
Read the luster
Hold the specimen under a strong light. Barquillite typically shows a metallic luster.
4
Match the color range
Compare against the expected color range: dark gray, black.
5
Look at form & habit
Crystal system: orthorhombic. Typical habit: tabular crystals, massive.

Often confused with

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

mineral

Germanite

Mohs 4

How to tell apart: Germanite is the harder of the two (Mohs 4 vs. 2.5-3); streak differs, so Barquillite leaves grey-black, Germanite leaves black.

How to tell apart: Renierite is the harder of the two (Mohs 4.5 vs. 2.5-3); streak differs, so Barquillite leaves grey-black, Renierite leaves black.

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Often found alongside barquillite

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

All properties

Chemical formula: Cu₂HgGeS₄
Mohs hardness: 2.5-3
Density: 6.12 g/cm³
Colors: Dark Gray Black
Streak: Grey-black
Luster: Metallic
Transparency: Opaque
Crystal system: Orthorhombic
Crystal habit: Tabular Crystals, Massive
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: Hydrothermal Veins
Typical price: $100-500 thumbnail

Where rockhounds find barquillite

Classic worldwide localities

Bor Pit, Dalnegorsk, Russia

Field-hunting tip

Look in hydrothermal veins country, the host setting where barquillite typically forms. If you start seeing galena, sphalerite, pyrite in float, you are in the right ground. Field specimens usually show a tabular crystals, massive habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify barquillite?+

Mohs hardness is 2.5-3. It typically shows a metallic luster. The streak is grey-black. Common colors include dark gray, black.

Where is barquillite found?+

Notable localities include Bor Pit, Dalnegorsk, Russia.

How much is barquillite 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 barquillite safe to handle?+

It contains toxic constituents. Contains mercury and copper; handle with care, avoid creating dust, and wash hands thoroughly after handling. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like barquillite?+

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

What minerals are found with barquillite?+

Barquillite commonly co-occurs with Galena, Sphalerite, Pyrite, Chalcopyrite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does barquillite form in?+

Barquillite typically forms in hydrothermal veins. Working float back to the host body is the standard way to chase a fresh occurrence.

What is barquillite used for?+

Barquillite is used in collector.

Find barquillite on the map

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