Möhnite is a rare potassium sodium sulfate, typically light brown to brown. Associated minerals include salammoniac, halite and joanneumite. It was first described from Pabellón de Pica mountain, 1.5 km south of Chanabaya, Iquique Province, Tarapacá Region, Chile.

Hardness

Mohs

Transparency

Transparent

mineralrare

Möhnite

Hardness: 3
Transparency: Transparent

Is this möhnite?

3-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 möhnite with a known reference. Möhnite sits at Mohs 3, softer than the next harder reference, harder than the previous one.
2
Match the color range
Compare against the expected color range: brown.
3
Look at form & habit
Crystal system: trigonal. Typical habit: tabular crystals, massive, granular.

Often confused with

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

Often found alongside möhnite

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

All properties

Chemical formula: (NH₄)K₂Na(SO₄)₂
Mohs hardness: 3
Density: 2.4 g/cm³
Colors: Brown
Transparency: Transparent
Crystal system: Trigonal
Crystal habit: Tabular crystals, massive, granular
Cleavage: None observed
Rarity: Rare
Uses: Collector
Host rock: A secondary mineral at the contact between the weathering zone of a bird guano deposit and an underlying chalcopyrite-bearing gabbro

Where rockhounds find möhnite

Classic worldwide localities

Pabellón de Pica mountain, 1.5 km south of Chanabaya, Iquique Province, Tarapacá Region, Chile

Field-hunting tip

Where it forms: A secondary mineral at the contact between the weathering zone of a bird guano deposit and an underlying chalcopyrite-bearing gabbro. If you start seeing salammoniac, halite, joanneumite in float, you are in the right ground. Typical habit: tabular crystals, massive, granular. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify möhnite?+

Mohs hardness is 3. Common colors include brown.

Where is möhnite found?+

Notable localities include Pabellón de Pica mountain, 1.5 km south of Chanabaya, Iquique Province, Tarapacá Region, Chile.

What rocks look like möhnite?+

Möhnite is most often confused with Galena, Anglesite, Lanarkite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with möhnite?+

Möhnite commonly co-occurs with Salammoniac, Halite, Joanneumite, Natroxalate, Nitratine, Chanabayaite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does möhnite form in?+

Where it forms: A secondary mineral at the contact between the weathering zone of a bird guano deposit and an underlying chalcopyrite-bearing gabbro. Working float back to the host body is the standard way to chase a fresh occurrence.

What is möhnite used for?+

Möhnite is used in collector.

Find möhnite on the map

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