Tiemannite is a rare mercury selenide mineral typically found as massive or granular aggregates within hydrothermal vein systems. It is characterized by its heavy weight, metallic luster, and black streak, often appearing alongside other selenium or mercury minerals.

Hardness

2.5

Mohs

Luster

Metallic

Streak

Black

Transparency

Opaque

mineralrare

Tiemannite

Also: seleniomercurite

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

Is this tiemannite?

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 tiemannite with a known reference. Tiemannite sits at Mohs 2.5 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Tiemannite leaves a black streak.
3
Read the luster
Hold the specimen under a strong light. Tiemannite typically shows a metallic luster.
4
Match the color range
Compare against the expected color range: steel-gray, iron-black.
5
Look at form & habit
Crystal system: cubic. Typical habit: massive, granular, rarely as small tetrahedrons or dodecahedrons.

Often confused with

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

Often found alongside tiemannite

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

All properties

Chemical formula: HgSe
Mohs hardness: 2.5
Density: 8.19-8.47 g/cm³
Colors: Steel-gray Iron-black
Streak: Black
Luster: Metallic
Transparency: Opaque
Crystal system: Cubic
Crystal habit: Massive, Granular, Rarely as Small Tetrahedrons or Dodecahedrons
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: Hydrothermal Veins
Typical price: $50-300 per specimen

Where rockhounds find tiemannite

Classic worldwide localities

Harz Mountains, Germany
Marysvale, Utah, USA
Sierra de Catorce, Mexico
Kamchatka, Russia

Field-hunting tip

Look in hydrothermal veins country — that is the host setting where tiemannite typically forms. If you start seeing cinnabar, calcite, barite in float, you are in the right ground. Field specimens usually show a massive, granular, rarely as small tetrahedrons or dodecahedrons habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify tiemannite?+

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

Where is tiemannite found?+

Notable localities include Harz Mountains, Germany; Marysvale, Utah, USA; Sierra de Catorce, Mexico; Kamchatka, Russia.

How much is tiemannite 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 tiemannite safe to handle?+

It contains toxic constituents. Contains mercury and selenium. Handle with extreme care, do not inhale dust, and wash hands thoroughly after handling. Not suitable for casual handling or lapidary work. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like tiemannite?+

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

What minerals are found with tiemannite?+

Tiemannite commonly co-occurs with Cinnabar, Calcite, Barite, Pyrite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does tiemannite form in?+

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

What is tiemannite used for?+

Tiemannite is used in collector.

Find tiemannite on the map

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