Lautenthalite is a rare secondary mineral typically found as tiny, delicate acicular crystals or radiating groups in lead-copper mining deposits. It is specifically known from the historic mining district of Lautenthal in the Harz Mountains of Germany.

Hardness

2.5

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent

mineralrareEttringite Group family

Lautenthalite

Hardness: 2.5
Luster: Vitreous
Streak: White
Transparency: Transparent

Is this lautenthalite?

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 lautenthalite with a known reference. Lautenthalite sits at Mohs 2.5, 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: vitreous.
4
Match the color range
Compare against the expected color range: blue green, green, greenish blue.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: acicular crystals, radiating sprays.

Often confused with

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

How to tell apart: Thaumasite is the harder of the two (Mohs 3.5 vs. 2.5).

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Often found alongside lautenthalite

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

All properties

Chemical formula: PbCu₄(SO₄)₂(OH)₆·3H₂O
Mohs hardness: 2.5
Density: 3.84 g/cm³
Colors: Blue green Green Greenish blue
Streak: White
Luster: Vitreous
Transparency: Transparent
Crystal system: Monoclinic
Crystal habit: Acicular crystals, radiating sprays
Cleavage: On {001} and {010}, good
Rarity: Rare
Uses: Collector
Host rock: Formed in the oxidation zone of Pb–Cu sulfide deposits (Wales); an oxidation product in cavities in smelter slag (Germany, Austria, Scotland)

Where rockhounds find lautenthalite

Classic worldwide localities

Öblarn, Steiermark, Austria
Found at the Meadowfoot smelter, northwest of Wanlockhead, Dumfriesshire, Scotland
Hendrefelen mine, Central Wales district, Wales
Dyfed, at the Penrhiw mine, Ystumtuen, and the Frongoch mine, Wales

Field-hunting tip

Where it forms: Formed in the oxidation zone of Pb–Cu sulfide deposits (Wales); an oxidation product in cavities in smelter slag (Germany, Austria, Scotland). If you start seeing anglesite, devilline–serpierite, galena in float, you are in the right ground. Typical habit: acicular crystals, radiating sprays. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify lautenthalite?+

Mohs hardness is 2.5. Luster: vitreous. The streak is white. Common colors include blue green, green, greenish blue.

Where is lautenthalite found?+

Notable localities include Öblarn, Steiermark, Austria; Found at the Meadowfoot smelter, northwest of Wanlockhead, Dumfriesshire, Scotland; Hendrefelen mine, Central Wales district, Wales; Dyfed, at the Penrhiw mine, Ystumtuen, and the Frongoch mine, Wales.

Is lautenthalite safe to handle?+

Lautenthalite contains copper and lead. Contains lead and copper; wash hands thoroughly after handling and avoid ingestion or inhalation of dust.

What rocks look like lautenthalite?+

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

What minerals are found with lautenthalite?+

Lautenthalite commonly co-occurs with Anglesite, Devilline–serpierite, Galena, Linarite, Brochantite, Schulenbergite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does lautenthalite form in?+

Where it forms: Formed in the oxidation zone of Pb–Cu sulfide deposits (Wales); an oxidation product in cavities in smelter slag (Germany, Austria, Scotland). Working float back to the host body is the standard way to chase a fresh occurrence.

What is lautenthalite used for?+

Lautenthalite is used in collector.

Find lautenthalite on the map

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