Neustädtelite is a rare bismuth-iron arsenate mineral primarily found in oxidized hydrothermal deposits. Collectors usually find it as small, yellowish, platy crystals forming distinct radial or rosette-like aggregates in association with other rare arsenate minerals.

Hardness

4.5

Mohs

Luster

Adamantine

Streak

Light brown

Transparency

Transparent to translucent

mineralrare

Neustädtelite

Hardness: 4.5
Luster: Adamantine
Streak: Light brown
Transparency: Transparent to translucent

Is this neustädtelite?

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 neustädtelite with a known reference. Neustädtelite 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. Streak: light brown.
3
Read the luster
Hold the specimen under a strong light. Luster: adamantine.
4
Match the color range
Compare against the expected color range: brown.
5
Look at form & habit
Crystal system: triclinic. Typical habit: tabular.

Often confused with

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

mineral

Mixite

Mohs 3-4

How to tell apart: Streak differs, so Neustädtelite leaves light brown, Mixite leaves pale bluish green; luster reads adamantine on Neustädtelite and vitreous, silky in aggregates on Mixite.

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Often found alongside neustädtelite

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

All properties

Chemical formula: Bi₂Fe(Fe,Co)₂(AsO₄)₂(O,OH)₄
Mohs hardness: 4.5
Density: 5.81 g/cm³
Colors: Brown
Streak: Light brown
Luster: Adamantine
Transparency: Transparent to translucent
Crystal system: Triclinic
Crystal habit: Tabular
Cleavage: Good on {001}
Rarity: Rare
Uses: Collector
Host rock: In vugs in quartz collected on waste piles from mining activity

Where rockhounds find neustädtelite

Classic worldwide localities

Dumps of the Güldener Falk mine, near Schneeberg-Neustädtel, Saxony, Germany
Also, from the Friedrich-Wilhelm adit, Friedensgruber vein, near Lichtenberg, Bavaria, Germany

Field-hunting tip

Where it forms: In vugs in quartz collected on waste piles from mining activity. If you start seeing cobaltneustädtelite, quartz, preisingerite in float, you are in the right ground. Typical habit: tabular. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify neustädtelite?+

Mohs hardness is 4.5. Luster: adamantine. The streak is light brown. Common colors include brown.

Where is neustädtelite found?+

Notable localities include Dumps of the Güldener Falk mine, near Schneeberg-Neustädtel, Saxony, Germany; Also, from the Friedrich-Wilhelm adit, Friedensgruber vein, near Lichtenberg, Bavaria, Germany.

Is neustädtelite safe to handle?+

Neustädtelite contains arsenic and cobalt and calls for real care. Contains arsenic, handle with care and wash hands thoroughly after handling. Do not ingest or inhale dust.

What rocks look like neustädtelite?+

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

What minerals are found with neustädtelite?+

Neustädtelite commonly co-occurs with Cobaltneustädtelite, Quartz, Preisingerite, Mixite, Zeunerite, Bismutite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does neustädtelite form in?+

Where it forms: In vugs in quartz collected on waste piles from mining activity. Working float back to the host body is the standard way to chase a fresh occurrence.

What is neustädtelite used for?+

Neustädtelite is used in collector.

Find neustädtelite on the map

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