Challacolloite is a very rare potassium lead chloride mineral discovered at its namesake locality in the Challacollo mine of Chile. It typically forms as thin crusts or coatings in volcanic fumarole environments and is often associated with other halide minerals. Due to its extreme rarity and tendency to form small, fragile aggregates, it is primarily sought after by advanced systematic mineral collectors.

Hardness

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent

mineralrare

Challacolloite

Hardness: 2
Luster: Vitreous
Streak: White
Transparency: Transparent

Is this challacolloite?

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 challacolloite with a known reference. Challacolloite sits at Mohs 2 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Challacolloite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Challacolloite typically shows a vitreous luster.
4
Match the color range
Compare against the expected color range: white, colorless.
5
Look at form & habit
Crystal system: cubic. Typical habit: crusts, aggregates of minute crystals.

Often confused with

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

mineral

Cotunnite

Mohs 2.5

How to tell apart: Luster reads vitreous on Challacolloite and adamantine on Cotunnite.

Compare →

Often found alongside challacolloite

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

All properties

Chemical formula: KPb₂Cl₅
Mohs hardness: 2
Density: 2.83 g/cm³
Colors: White Colorless
Streak: White
Luster: Vitreous
Transparency: Transparent
Crystal system: Cubic
Crystal habit: Crusts, Aggregates of Minute Crystals
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: Fumarolic Deposits
Typical price: $50-300 per specimen

Where rockhounds find challacolloite

Classic worldwide localities

Challacollo mine, Chile

Field-hunting tip

Look in fumarolic deposits country — that is the host setting where challacolloite typically forms. If you start seeing cotunnite, halite, sylvite in float, you are in the right ground. Field specimens usually show a crusts, aggregates of minute crystals habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify challacolloite?+

Mohs hardness is 2. It typically shows a vitreous luster. The streak is white. Common colors include white, colorless.

Where is challacolloite found?+

Notable localities include Challacollo mine, Chile.

How much is challacolloite 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 challacolloite safe to handle?+

It contains toxic constituents. Contains lead, which is toxic if ingested or inhaled as dust; wash hands thoroughly after handling and keep away from food. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like challacolloite?+

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

What minerals are found with challacolloite?+

Challacolloite commonly co-occurs with cotunnite, halite, sylvite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does challacolloite form in?+

Challacolloite typically forms in fumarolic deposits. Working float back to the host body is the standard way to chase a fresh occurrence.

What is challacolloite used for?+

Challacolloite is used in collector.

Find challacolloite on the map

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