Walthierite is a rare barium-dominant member of the alunite group often found in hydrothermally altered volcanic environments. Collectors typically look for small, white, platy crystals or granular masses formed within acid-sulfate leaching zones.

Hardness

3.5

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent

mineralrareAlunite Supergroup family

Walthierite

Hardness: 3.5
Luster: Vitreous
Streak: White
Transparency: Transparent

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Is this walthierite?

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 walthierite with a known reference. Walthierite sits at Mohs 3.5, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Walthierite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Walthierite typically shows a vitreous luster.
4
Match the color range
Compare against the expected color range: white, colorless.
5
Look at form & habit
Crystal system: trigonal. Typical habit: platy crystals, granular aggregates.

Often confused with

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

How to tell apart: Streak differs, so Walthierite leaves white, Jarosite leaves yellow.

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Often found alongside walthierite

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

All properties

Chemical formula: Ba₀.₅Al₃(SO₄)₂(OH)₆
Mohs hardness: 3.5
Density: 3.51 g/cm³
Colors: White Colorless
Streak: White
Luster: Vitreous
Transparency: Transparent
Crystal system: Trigonal
Crystal habit: Platy Crystals, Granular Aggregates
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: Hydrothermal Alteration Zones in Volcanic Rocks
Typical price: $50-300 per specimen

Where rockhounds find walthierite

Classic worldwide localities

Walthier Mine, Germany
Goldfield, Nevada, USA
Iron Mountain, California, USA

Field-hunting tip

Look in hydrothermal alteration zones in volcanic rocks country, the host setting where walthierite typically forms. If you start seeing quartz, alunite, jarosite in float, you are in the right ground. Field specimens usually show a platy crystals, granular aggregates habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify walthierite?+

Mohs hardness is 3.5. It typically shows a vitreous luster. The streak is white. Common colors include white, colorless.

Where is walthierite found?+

Notable localities include Walthier Mine, Germany; Goldfield, Nevada, USA; Iron Mountain, California, USA.

How much is walthierite worth?+

Typical asking prices fall in the range of $50-300 per specimen. Quality, size, and provenance can move individual specimens well outside that range.

What rocks look like walthierite?+

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

What minerals are found with walthierite?+

Walthierite commonly co-occurs with Quartz, Alunite, Jarosite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does walthierite form in?+

Walthierite typically forms in hydrothermal alteration zones in volcanic rocks. Working float back to the host body is the standard way to chase a fresh occurrence.

What is walthierite used for?+

Walthierite is used in collector.

Find walthierite on the map

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