Rappoldite is a rare arsenate mineral that typically forms as small, colorless to pale yellow drusy aggregates. It is primarily identified through its occurrence in specific arsenic-rich hydrothermal vein systems where it manifests as a secondary mineral.

Hardness

4-5

Mohs

Luster

Vitreous

Streak

White

Transparency

Translucent

mineralrareGorceixite Group family

Rappoldite

Hardness: 4-5
Luster: Vitreous
Streak: White
Transparency: Translucent

Is this rappoldite?

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

Often confused with

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

Often found alongside rappoldite

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

All properties

Chemical formula: CaZn₂(AsO₄)₂(OH)₂·H₂O
Mohs hardness: 4-5
Density: 3.31 g/cm³
Colors: White Colorless Pale Yellow
Streak: White
Luster: Vitreous
Transparency: Translucent
Crystal system: Trigonal
Crystal habit: Drusy Aggregates
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: Hydrothermal Veins in Metamorphic Rocks
Typical price: $50-300 per specimen depending on size and quality

Where rockhounds find rappoldite

Classic worldwide localities

Rappold, Germany

Field-hunting tip

Look in hydrothermal veins in metamorphic rocks country — that is the host setting where rappoldite typically forms. If you start seeing arsenopyrite, pharmacolite, picropharmacolite in float, you are in the right ground. Field specimens usually show a drusy aggregates habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify rappoldite?+

Mohs hardness is 4-5. It typically shows a vitreous luster. The streak is white. Common colors include white, colorless, pale yellow.

Where is rappoldite found?+

Notable localities include Rappold, Germany.

How much is rappoldite worth?+

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

Is rappoldite safe to handle?+

It contains toxic constituents. Contains arsenic. Wash hands thoroughly after handling and avoid inhaling dust or ingesting particles. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like rappoldite?+

Rappoldite is most often confused with Gorceixite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with rappoldite?+

Rappoldite commonly co-occurs with Arsenopyrite, Pharmacolite, Picropharmacolite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does rappoldite form in?+

Rappoldite typically forms in hydrothermal veins in metamorphic rocks. Working float back to the host body is the standard way to chase a fresh occurrence.

What is rappoldite used for?+

Rappoldite is used in collector.

Find rappoldite on the map

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