Mazzettiite is an extremely rare silver-mercury-lead-antimony telluride mineral found primarily in epithermal gold-silver deposits. It typically occurs as microscopic grains within complex sulfide-telluride ores and is prized by advanced mineral collectors for its unique chemistry.

Hardness

3-3.5

Mohs

Luster

Metallic

Streak

Black

Transparency

Opaque

mineralrare

Mazzettiite

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

No image

Is this mazzettiite?

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 mazzettiite with a known reference. Mazzettiite 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: light gray.
5
Look at form & habit
Crystal system: orthorhombic. Typical habit: anhedral grains, subhedral crystals.

Often confused with

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

Often found alongside mazzettiite

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

All properties

Chemical formula: Ag₃HgPbSbTe₅
Mohs hardness: 3-3.5
Density: 9.04 g/cm³
Colors: Light gray
Streak: Black
Luster: Metallic
Transparency: Opaque
Crystal system: Orthorhombic
Crystal habit: Anhedral grains, subhedral crystals
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: A rare mineral in a hydrothermal telluride deposit

Where rockhounds find mazzettiite

Classic worldwide localities

Findley Gulch, Bonanza mining district, Saguache County, Colorado, USA

Field-hunting tip

Where it forms: A rare mineral in a hydrothermal telluride deposit. If you start seeing altaite, galena, quartz in float, you are in the right ground. Typical habit: anhedral grains, subhedral crystals. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify mazzettiite?+

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

Where is mazzettiite found?+

Notable localities include Findley Gulch, Bonanza mining district, Saguache County, Colorado, USA.

Is mazzettiite safe to handle?+

Mazzettiite contains antimony, lead and mercury and calls for real care. Contains mercury, lead, and tellurium. Should be handled with care; wash hands thoroughly after handling and avoid inhaling dust.

What rocks look like mazzettiite?+

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

What minerals are found with mazzettiite?+

Mazzettiite commonly co-occurs with Altaite, Galena, Quartz. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does mazzettiite form in?+

Where it forms: A rare mineral in a hydrothermal telluride deposit. Working float back to the host body is the standard way to chase a fresh occurrence.

What is mazzettiite used for?+

Mazzettiite is used in collector.

Find mazzettiite on the map

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