Arsiccioite is an extremely rare sulfosalt mineral found in the Apuan Alps of Italy. It occurs as small, black, metallic crystals typically associated with mercury and thallium-bearing minerals in hydrothermal vein systems.

Hardness

3.5-4

Mohs

Luster

Metallic

Streak

Black

Transparency

Opaque

mineralrare

Arsiccioite

Hardness: 3.5-4
Luster: Metallic
Streak: Black
Transparency: Opaque

Is this arsiccioite?

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 arsiccioite with a known reference. Arsiccioite sits at Mohs 3.5-4, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Arsiccioite leaves a black streak.
3
Read the luster
Hold the specimen under a strong light. Arsiccioite typically shows a metallic luster.
4
Match the color range
Compare against the expected color range: black.
5
Look at form & habit
Crystal system: tetragonal. Typical habit: equant to subhedral crystals.

Often confused with

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

Often found alongside arsiccioite

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

All properties

Chemical formula: HgAgTlAs₂S₆
Mohs hardness: 3.5-4
Density: 4.86 g/cm³
Colors: Black
Streak: Black
Luster: Metallic
Transparency: Opaque
Crystal system: Tetragonal
Crystal habit: Equant to Subhedral Crystals
Cleavage: None Observed
Rarity: Rare
Uses: Collector
Host rock: Hydrothermal Veins in Metamorphic Rocks
Typical price: $200-1000+ per specimen

Where rockhounds find arsiccioite

Classic worldwide localities

Apuan Alps, Tuscany, Italy

Field-hunting tip

Look in hydrothermal veins in metamorphic rocks country, the host setting where arsiccioite typically forms. If you start seeing cinnabar, realgar, pyrite in float, you are in the right ground. Field specimens usually show a equant to subhedral crystals habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify arsiccioite?+

Mohs hardness is 3.5-4. It typically shows a metallic luster. The streak is black. Common colors include black.

Where is arsiccioite found?+

Notable localities include Apuan Alps, Tuscany, Italy.

How much is arsiccioite 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 arsiccioite safe to handle?+

It contains toxic constituents. Contains mercury, silver, thallium, and arsenic. Always wash hands after handling and avoid inhaling dust; store securely to avoid ingestion or contamination. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like arsiccioite?+

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

What minerals are found with arsiccioite?+

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

What kind of rock does arsiccioite form in?+

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

What is arsiccioite used for?+

Arsiccioite is used in collector.

Find arsiccioite on the map

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