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

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

Compare →

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, 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.