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

No image

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 — 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 — Barquillite leaves grey-black, Renierite leaves black.

Compare →

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 — that is 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.