Vaughanite is an extremely rare thallium-mercury sulfosalt primarily found in gold-bearing hydrothermal deposits. Collectors usually encounter it as microscopic grains embedded within ore samples, as large crystals are virtually unknown.

Hardness

3-3.5

Mohs

Luster

Metallic

Streak

Black

Transparency

Opaque

mineralrare

Vaughanite

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

Is this vaughanite?

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 vaughanite with a known reference. Vaughanite 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. Streak: black.
3
Read the luster
Hold the specimen under a strong light. Luster: metallic.
4
Match the color range
Compare against the expected color range: black.
5
Look at form & habit
Crystal system: triclinic. Typical habit: anhedral grains, microscopic crystals.

Often confused with

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

How to tell apart: Vaughanite is noticeably harder (Mohs 3-3.5 vs. 2); streak differs, so Vaughanite leaves black, Livingstonite leaves red; luster reads metallic on Vaughanite and adamantine to metallic on Livingstonite.

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Often found alongside vaughanite

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

All properties

Chemical formula: TlHgSb₄S₇
Mohs hardness: 3-3.5
Density: 5.56 g/cm³
Colors: Black
Streak: Black
Luster: Metallic
Transparency: Opaque
Crystal system: Triclinic
Crystal habit: Anhedral grains, microscopic crystals
Cleavage: A weak parting was observed
Rarity: Rare
Uses: Collector
Host rock: A very rare primary mineral found in drill core from an epithermal-hydrothermal gold deposit

Where rockhounds find vaughanite

Classic worldwide localities

Golden Giant orebody, Hemlo gold deposit, 35 km east of Marathon, Ontario, Canada (type locality)

Field-hunting tip

Where it forms: A very rare primary mineral found in drill core from an epithermal-hydrothermal gold deposit. If you start seeing pääkkönenite, stibarsen, realgar in float, you are in the right ground. Typical habit: anhedral grains, microscopic crystals. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify vaughanite?+

Mohs hardness is 3-3.5. Luster: metallic. The streak is black. Common colors include black.

Where is vaughanite found?+

Notable localities include Golden Giant orebody, Hemlo gold deposit, 35 km east of Marathon, Ontario, Canada (type locality).

Is vaughanite safe to handle?+

Vaughanite contains antimony, mercury and thallium and calls for real care. Contains antimony, mercury and thallium, which are toxic if ingested or inhaled as dust. Wash hands thoroughly after handling and avoid creating dust.

What rocks look like vaughanite?+

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

What minerals are found with vaughanite?+

Vaughanite commonly co-occurs with Pääkkönenite, Stibarsen, Realgar, Arsenic, Chalcostibite, Quartz. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does vaughanite form in?+

Where it forms: A very rare primary mineral found in drill core from an epithermal-hydrothermal gold deposit. Working float back to the host body is the standard way to chase a fresh occurrence.

What is vaughanite used for?+

Vaughanite is used in collector.

Find vaughanite on the map

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