Charmarite is a rare member of the hydrotalcite group, typically orange-brown to pale brown. It occurs in silicate and carbonate cavities and in pegmatites cutting nepheline syenite, and is the manganese-dominant analogue of quintinite. It is prized by advanced collectors of microminerals.

Hardness

Mohs

Luster

Adamantine

Streak

White

Transparency

Transparent

mineralrareHydrotalcite Group family

Charmarite

Hardness: ~3
Luster: Adamantine
Streak: White
Transparency: Transparent

Is this charmarite?

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 charmarite with a known reference. Charmarite sits at Mohs ~3, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Streak: white.
3
Read the luster
Hold the specimen under a strong light. Luster: adamantine.
4
Match the color range
Compare against the expected color range: colorless, yellow.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: platy crystals, granular aggregates.

Often confused with

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

mineral

Hydrotalcite

Mohs 2

How to tell apart: Charmarite is noticeably harder (Mohs ~3 vs. 2); luster reads adamantine on Charmarite and satiny to greasy or waxy on Hydrotalcite.

Compare →

Often found alongside charmarite

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

All properties

Chemical formula: Mn²⁺₄Al₂(CO₃)(OH)₁₂·3H₂O
Mohs hardness: ~3
Density: 6.30-6.49 g/cm³
Colors: Colorless Yellow
Streak: White
Luster: Adamantine
Transparency: Transparent
Crystal system: Monoclinic
Crystal habit: Platy crystals, granular aggregates
Cleavage: {100} and {010}
Rarity: Rare
Uses: Collector
Host rock: In the oxidized zone of a lead-bearing U–V deposit (Mounana mine, Gabon)

Where rockhounds find charmarite

Classic worldwide localities

Mounana uranium mine, Franceville, Gabon
Kusu deposit, 85 km south of Kinshasa, Bas-Congo Province, Congo (Bas-Zaire Province, Zaire)
St. Andreasberg, Harz Mountains, Germany
Found at Vrančice, near Příbram, Czech Republic

Field-hunting tip

Where it forms: In the oxidized zone of a lead-bearing U–V deposit (Mounana mine, Gabon). If you start seeing francevillite, wulfenite in float, you are in the right ground. Typical habit: platy crystals, granular aggregates. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify charmarite?+

Mohs hardness is ~3. Luster: adamantine. The streak is white. Common colors include colorless, yellow.

Where is charmarite found?+

Notable localities include Mounana uranium mine, Franceville, Gabon; Kusu deposit, 85 km south of Kinshasa, Bas-Congo Province, Congo (Bas-Zaire Province, Zaire); St. Andreasberg, Harz Mountains, Germany; Found at Vrančice, near Příbram, Czech Republic.

What rocks look like charmarite?+

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

What minerals are found with charmarite?+

Charmarite commonly co-occurs with Francevillite, Wulfenite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does charmarite form in?+

Where it forms: In the oxidized zone of a lead-bearing U–V deposit (Mounana mine, Gabon). Working float back to the host body is the standard way to chase a fresh occurrence.

What is charmarite used for?+

Charmarite is used in collector.

Find charmarite on the map

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