Llantenesite is a rare magnesium-iron sulfate mineral belonging to the copiapite group. It is typically found as small, fragile tabular crystals or yellow powdery crusts in the oxidized zones of sulfate-rich mineral deposits.

Hardness

2.5-3

Mohs

Luster

Pearly

Streak

Yellow

Transparency

Translucent

mineralrareCopiapite Group family

Llantenesite

Hardness: 2.5-3
Luster: Pearly
Streak: Yellow
Transparency: Translucent

No image

Is this llantenesite?

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 llantenesite with a known reference. Llantenesite sits at Mohs 2.5-3 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Llantenesite leaves a yellow streak.
3
Read the luster
Hold the specimen under a strong light. Llantenesite typically shows a pearly luster.
4
Match the color range
Compare against the expected color range: yellow, yellowish-orange.
5
Look at form & habit
Crystal system: triclinic. Typical habit: tabular crystals, crusts, efflorescent aggregates.

Often confused with

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

How to tell apart: Streak differs — Llantenesite leaves yellow, Aluminocopiapite leaves white.

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Often found alongside llantenesite

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

All properties

Chemical formula: MgFe₄³⁺(SO₄)₆(OH)₂·20H₂O
Mohs hardness: 2.5-3
Density: 2.16 g/cm³
Colors: Yellow Yellowish-orange
Streak: Yellow
Luster: Pearly
Transparency: Translucent
Crystal system: Triclinic
Crystal habit: Tabular Crystals, Crusts, Efflorescent Aggregates
Cleavage: Perfect
Rarity: Rare
Uses: Collector
Host rock: Oxidized Zones of Sulfide Ore Deposits
Typical price: $20-100 for small specimen

Where rockhounds find llantenesite

Classic worldwide localities

La Alcaparrosa mine, Argentina
Sierra Gorda, Chile
Chuquicamata, Chile

Field-hunting tip

Look in oxidized zones of sulfide ore deposits country — that is the host setting where llantenesite typically forms. If you start seeing copiapite, jarosite, melanterite in float, you are in the right ground. Field specimens usually show a tabular crystals, crusts, efflorescent aggregates habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify llantenesite?+

Mohs hardness is 2.5-3. It typically shows a pearly luster. The streak is yellow. Common colors include yellow, yellowish-orange.

Where is llantenesite found?+

Notable localities include La Alcaparrosa mine, Argentina; Sierra Gorda, Chile; Chuquicamata, Chile.

How much is llantenesite worth?+

Typical asking prices fall in the range of $20-100 for small specimen. Quality, size, and provenance can move individual specimens well outside that range.

What rocks look like llantenesite?+

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

What minerals are found with llantenesite?+

Llantenesite commonly co-occurs with Copiapite, Jarosite, Melanterite, Gypsum. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does llantenesite form in?+

Llantenesite typically forms in oxidized zones of sulfide ore deposits. Working float back to the host body is the standard way to chase a fresh occurrence.

What is llantenesite used for?+

Llantenesite is used in collector.

Find llantenesite on the map

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