Avicennite is an extremely rare thallium oxide mineral that typically occurs as tiny, metallic black grains within hydrothermal ore deposits. It is named in honor of the Persian philosopher Avicenna (Ibn Sina). Due to its high thallium content and scarcity, it is highly sought after by advanced systematic mineral collectors.

Hardness

Mohs

Luster

Metallic

Streak

Black

Transparency

Opaque

mineralrare

Avicennite

Hardness: 6
Luster: Metallic
Streak: Black
Transparency: Opaque

Is this avicennite?

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 avicennite with a known reference. Avicennite sits at Mohs 6 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Avicennite leaves a black streak.
3
Read the luster
Hold the specimen under a strong light. Avicennite typically shows a metallic luster.
4
Match the color range
Compare against the expected color range: black, grayish-black.
5
Look at form & habit
Crystal system: cubic. Typical habit: grains.

Often confused with

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

mineral

Iron Ore

Mohs 5-6.5

How to tell apart: Streak differs — Avicennite leaves black, Iron Ore leaves reddish-brown to black; luster reads metallic on Avicennite and metallic to submetallic on Iron Ore.

Often found alongside avicennite

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

All properties

Chemical formula: Tl₂O₃
Mohs hardness: 6
Density: 9.5 g/cm³
Colors: Black Grayish-black
Streak: Black
Luster: Metallic
Transparency: Opaque
Crystal system: Cubic
Crystal habit: Grains
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: Hydrothermal Veins
Typical price: $200-1000+ per specimen

Where rockhounds find avicennite

Classic worldwide localities

Dzhil-Nau, Uzbekistan
Allchar, North Macedonia

Field-hunting tip

Look in hydrothermal veins country — that is the host setting where avicennite typically forms. If you start seeing realgar, orpiment, lorandite in float, you are in the right ground. Field specimens usually show a grains habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify avicennite?+

Mohs hardness is 6. It typically shows a metallic luster. The streak is black. Common colors include black, grayish-black.

Where is avicennite found?+

Notable localities include Dzhil-Nau, Uzbekistan; Allchar, North Macedonia.

How much is avicennite worth?+

Typical asking prices fall in the range of $200-1000+ per specimen. Quality, size, and provenance can move individual specimens well outside that range.

Is avicennite safe to handle?+

It contains toxic constituents. Contains thallium, which is highly toxic. Handle with gloves and wash hands thoroughly after contact; do not inhale dust. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like avicennite?+

Avicennite is most often confused with Iron Ore, Magnetite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with avicennite?+

Avicennite commonly co-occurs with Realgar, Orpiment, Lorandite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does avicennite form in?+

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

What is avicennite used for?+

Avicennite is used in collector.

Find avicennite on the map

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