Ustarasite is a rare lead bismuth sulfide mineral typically found in complex hydrothermal deposits. It is best identified through laboratory analysis as it visually resembles several other lead-bismuth sulfosalts, typically appearing as massive metallic gray aggregates.

Hardness

2.5-3

Mohs

Luster

Metallic

Streak

Black

Transparency

Opaque

mineralrare

Ustarasite

Hardness: 2.5-3
Luster: Metallic
Streak: Black
Transparency: Opaque

Is this ustarasite?

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 ustarasite with a known reference. Ustarasite 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. Ustarasite leaves a black streak.
3
Read the luster
Hold the specimen under a strong light. Ustarasite typically shows a metallic luster.
4
Match the color range
Compare against the expected color range: lead-gray, steel-gray.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: massive, anhedral grains.

Often confused with

Ustarasite 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 — Ustarasite leaves black, Galena leaves lead-gray.

How to tell apart: Streak differs — Ustarasite leaves black, Bismuthinite leaves lead-gray.

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Often found alongside ustarasite

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

All properties

Chemical formula: Pb₃Bi₄S₉
Mohs hardness: 2.5-3
Density: 6.8 g/cm³
Colors: Lead-gray Steel-gray
Streak: Black
Luster: Metallic
Transparency: Opaque
Crystal system: Monoclinic
Crystal habit: Massive, Anhedral Grains
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: Hydrothermal Sulfide Veins
Typical price: $50-300 per specimen

Where rockhounds find ustarasite

Classic worldwide localities

Ustarasai deposit, Kyrgyzstan
Banská Štiavnica, Slovakia
various hydrothermal vein deposits

Field-hunting tip

Look in hydrothermal sulfide veins country — that is the host setting where ustarasite typically forms. If you start seeing galena, bismuthinite, pyrite in float, you are in the right ground. Field specimens usually show a massive, anhedral grains habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify ustarasite?+

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

Where is ustarasite found?+

Notable localities include Ustarasai deposit, Kyrgyzstan; Banská Štiavnica, Slovakia; various hydrothermal vein deposits.

How much is ustarasite 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 ustarasite safe to handle?+

It contains toxic constituents. Contains lead and bismuth; wash hands thoroughly after handling and avoid inhaling dust or ingesting. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like ustarasite?+

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

What minerals are found with ustarasite?+

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

What kind of rock does ustarasite form in?+

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

What is ustarasite used for?+

Ustarasite is used in collector.

Find ustarasite on the map

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