Lausenite is a rare iron sulfate mineral that typically forms as an efflorescence or crust on decomposing iron sulfide minerals. It is highly unstable in humid conditions and can easily dehydrate or dissolve, making it a challenging mineral for collectors to store and display.

Hardness

2-3

Mohs

Luster

Silky

Streak

White

Transparency

Semitransparent

mineralrareSulfate Mineral family

Lausenite

Hardness: 2-3
Luster: Silky
Streak: White
Transparency: Semitransparent

Is this lausenite?

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 lausenite with a known reference. Lausenite sits at Mohs 2-3, 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: silky.
4
Match the color range
Compare against the expected color range: white.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: fibrous.

Often confused with

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

How to tell apart: Luster reads silky on Lausenite and vitreous on Szomolnokite.

How to tell apart: Luster reads silky on Lausenite and vitreous on Coquimbite.

Compare →

Often found alongside lausenite

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

All properties

Chemical formula: Fe₂(SO₄)₃(H₂O)₅
Mohs hardness: 2-3
Density: 2.2-2.3 g/cm³
Colors: White
Streak: White
Luster: Silky
Transparency: Semitransparent
Crystal system: Monoclinic
Crystal habit: Fibrous
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: A very rare mineral, formed as the result of burning of a pyritic orebody (United Verde mine, Arizona, USA); on a burning waste heap formed by oxidation of pyrite reacting with clay (Velikomostov-2 mine, Ukraine)

Where rockhounds find lausenite

Classic worldwide localities

United Verde mine, Jerome, Yavapai Co., Arizona, USA
Velikomostov-2 coal mine, L’vov-Volyn’ Basin, Ukraine

Field-hunting tip

Where it forms: A very rare mineral, formed as the result of burning of a pyritic orebody (United Verde mine, Arizona, USA); on a burning waste heap formed by oxidation of pyrite reacting with clay (Velikomostov-2 mine, Ukraine). If you start seeing copiapite, kieserite in float, you are in the right ground. Typical habit: fibrous. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify lausenite?+

Mohs hardness is 2-3. Luster: silky. The streak is white. Common colors include white.

Where is lausenite found?+

Notable localities include United Verde mine, Jerome, Yavapai Co., Arizona, USA; Velikomostov-2 coal mine, L’vov-Volyn’ Basin, Ukraine.

What rocks look like lausenite?+

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

What minerals are found with lausenite?+

Lausenite commonly co-occurs with Copiapite, Kieserite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does lausenite form in?+

Where it forms: A very rare mineral, formed as the result of burning of a pyritic orebody (United Verde mine, Arizona, USA); on a burning waste heap formed by oxidation of pyrite reacting with clay (Velikomostov-2 mine, Ukraine). Working float back to the host body is the standard way to chase a fresh occurrence.

What is lausenite used for?+

Lausenite is used in collector.

Find lausenite on the map

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