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, so 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, 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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