Metavoltine is a rare sulfate mineral that forms as a secondary alteration product in the oxidation zones of sulfide ore deposits. It is most easily identified by its characteristic hexagonal, micaceous plate habit and distinct yellow-orange coloration. Due to its solubility, it is best found in extremely arid environments where it can persist as thin crusts or small crystalline aggregates.

Hardness

2.5

Mohs

Luster

Vitreous

Streak

Yellow

Transparency

Translucent

mineralrare

Metavoltine

Hardness: 2.5
Luster: Vitreous
Streak: Yellow
Transparency: Translucent

No image

Is this metavoltine?

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 metavoltine with a known reference. Metavoltine 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. Metavoltine leaves a yellow streak.
3
Read the luster
Hold the specimen under a strong light. Metavoltine typically shows a vitreous luster.
4
Match the color range
Compare against the expected color range: yellow, orange, brown.
5
Look at form & habit
Crystal system: trigonal. Typical habit: hexagonal plates, micaceous aggregates, encrustations.

Often confused with

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

mineral

Copiapite

Mohs 2.5-3

How to tell apart: Luster reads vitreous on Metavoltine and pearly on Copiapite.

How to tell apart: Streak differs — Metavoltine leaves yellow, Coquimbite leaves white.

Often found alongside metavoltine

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

All properties

Chemical formula: K₂Na₆Fe³⁺₃(SO₄)₁₂(OH)₂·18H₂O
Mohs hardness: 2.5
Density: 2.55 g/cm³
Colors: Yellow Orange Brown
Streak: Yellow
Luster: Vitreous
Transparency: Translucent
Crystal system: Trigonal
Crystal habit: Hexagonal Plates, Micaceous Aggregates, Encrustations
Cleavage: Perfect Basal
Rarity: Rare
Uses: Collector
Host rock: Arid Oxidation Zones of Iron-bearing Sulfide Deposits
Typical price: $20-150 for micromounts and thumbnails

Where rockhounds find metavoltine

Classic worldwide localities

Alcaparrosa mine, Chile
Chuquicamata, Chile
Sierra Gorda, Chile
Iron Mountain, California, USA

Field-hunting tip

Look in arid oxidation zones of iron-bearing sulfide deposits country — that is the host setting where metavoltine typically forms. If you start seeing copiapite, coquimbite, fibroferrite in float, you are in the right ground. Field specimens usually show a hexagonal plates, micaceous aggregates, encrustations habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify metavoltine?+

Mohs hardness is 2.5. It typically shows a vitreous luster. The streak is yellow. Common colors include yellow, orange, brown.

Where is metavoltine found?+

Notable localities include Alcaparrosa mine, Chile; Chuquicamata, Chile; Sierra Gorda, Chile; Iron Mountain, California, USA.

How much is metavoltine worth?+

Typical asking prices fall in the range of $20-150 for micromounts and thumbnails. Quality, size, and provenance can move individual specimens well outside that range.

What rocks look like metavoltine?+

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

What minerals are found with metavoltine?+

Metavoltine commonly co-occurs with Copiapite, Coquimbite, Fibroferrite, Jarosite, Amarantite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does metavoltine form in?+

Metavoltine typically forms in arid oxidation zones of iron-bearing sulfide deposits. Working float back to the host body is the standard way to chase a fresh occurrence.

What is metavoltine used for?+

Metavoltine is used in collector.

Find metavoltine on the map

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