Dalnegroite is an extremely rare thallium-lead sulfosalt discovered in the skarn deposits of the Primorskiy Kray region in Russia. It typically occurs as small, lead-gray grains within complex sulfide-rich assemblages and is highly prized by advanced mineralogists for its unique composition.

Hardness

3-3.5

Mohs

Luster

Metallic

Streak

Black

Transparency

Opaque

mineralrareSulfosalt family

Dalnegroite

Hardness: 3-3.5
Luster: Metallic
Streak: Black
Transparency: Opaque

Is this dalnegroite?

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 dalnegroite with a known reference. Dalnegroite sits at Mohs 3-3.5, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Dalnegroite leaves a black streak.
3
Read the luster
Hold the specimen under a strong light. Dalnegroite typically shows a metallic luster.
4
Match the color range
Compare against the expected color range: lead-gray, dark gray.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: granular to massive.

Often confused with

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

mineral

Galena

Mohs 2.5

How to tell apart: Streak differs, so Dalnegroite leaves black, Galena leaves lead-gray.

How to tell apart: Streak differs, so Dalnegroite leaves black, Bournonite leaves steel-gray.

How to tell apart: Streak differs, so Dalnegroite leaves black, Sartorite leaves chocolate-brown.

Compare →

Often found alongside dalnegroite

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

All properties

Chemical formula: (Tl,Pb)₃AsS₃
Mohs hardness: 3-3.5
Density: 5.68 g/cm³
Colors: Lead-gray Dark Gray
Streak: Black
Luster: Metallic
Transparency: Opaque
Crystal system: Monoclinic
Crystal habit: Granular to Massive
Cleavage: None Observed
Rarity: Rare
Uses: Collector
Host rock: Skarn Deposits
Typical price: $50-300 per specimen

Where rockhounds find dalnegroite

Classic worldwide localities

Dal'negorsk, Russia

Field-hunting tip

Look in skarn deposits country, the host setting where dalnegroite typically forms. If you start seeing galena, sphalerite, pyrite in float, you are in the right ground. Field specimens usually show a granular to massive habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify dalnegroite?+

Mohs hardness is 3-3.5. It typically shows a metallic luster. The streak is black. Common colors include lead-gray, dark gray.

Where is dalnegroite found?+

Notable localities include Dal'negorsk, Russia.

How much is dalnegroite worth?+

Typical asking prices fall in the range of $50-300 per specimen. Quality, size, and provenance can move individual specimens well outside that range.

Is dalnegroite safe to handle?+

It contains toxic constituents. Contains thallium and arsenic; handle with care and wash hands thoroughly after contact to avoid ingestion or skin absorption. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like dalnegroite?+

Dalnegroite is most often confused with Galena, Bournonite, Sartorite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with dalnegroite?+

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

What kind of rock does dalnegroite form in?+

Dalnegroite typically forms in skarn deposits. Working float back to the host body is the standard way to chase a fresh occurrence.

What is dalnegroite used for?+

Dalnegroite is used in collector.

Find dalnegroite on the map

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