Nickellotharmeyerite is a rare arsenic-bearing mineral belonging to the Tsumcorite group. It is typically found as small, vibrant yellow to orange prismatic crystals or crusts in the oxidation zones of ore deposits. Due to its rarity and specific chemical requirements, it is primarily a target for advanced mineral collectors.

Hardness

4-5

Mohs

Luster

Vitreous

Streak

Yellow

Transparency

Translucent

mineralrareTsumcorite Group family

Nickellotharmeyerite

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

Is this nickellotharmeyerite?

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 nickellotharmeyerite with a known reference. Nickellotharmeyerite 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. Nickellotharmeyerite leaves a yellow streak.
3
Read the luster
Hold the specimen under a strong light. Nickellotharmeyerite 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: monoclinic. Typical habit: prismatic crystals, crusts.

Often confused with

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

mineral

Tsumcorite

Mohs 4.5

How to tell apart: Streak differs — Nickellotharmeyerite leaves yellow, Tsumcorite leaves yellowish.

How to tell apart: Streak differs — Nickellotharmeyerite leaves yellow, Cobalttsumcorite leaves light pink.

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Often found alongside nickellotharmeyerite

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

All properties

Chemical formula: CaNi₂(AsO₄)₂·2H₂O
Mohs hardness: 4-5
Density: 4.5-5.5 g/cm³
Colors: Yellow Orange Brown
Streak: Yellow
Luster: Vitreous
Transparency: Translucent
Crystal system: Monoclinic
Crystal habit: Prismatic Crystals, Crusts
Cleavage: Good
Rarity: Rare
Uses: Collector
Host rock: Oxidized Hydrothermal Arsenic-rich Deposits
Typical price: $50-300 per specimen

Where rockhounds find nickellotharmeyerite

Classic worldwide localities

Schneeberg, Saxony, Germany
Tsumeb, Namibia

Field-hunting tip

Look in oxidized hydrothermal arsenic-rich deposits country — that is the host setting where nickellotharmeyerite typically forms. If you start seeing pharmacolite, goethite, scorodite in float, you are in the right ground. Field specimens usually show a prismatic crystals, crusts habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify nickellotharmeyerite?+

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

Where is nickellotharmeyerite found?+

Notable localities include Schneeberg, Saxony, Germany; Tsumeb, Namibia.

How much is nickellotharmeyerite 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.

Is nickellotharmeyerite safe to handle?+

It contains toxic constituents. Contains arsenic, which is toxic if ingested or inhaled as dust. Handle with care, wash hands thoroughly after contact, and keep away from children. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like nickellotharmeyerite?+

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

What minerals are found with nickellotharmeyerite?+

Nickellotharmeyerite commonly co-occurs with Pharmacolite, Goethite, Scorodite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does nickellotharmeyerite form in?+

Nickellotharmeyerite typically forms in oxidized hydrothermal arsenic-rich deposits. Working float back to the host body is the standard way to chase a fresh occurrence.

What is nickellotharmeyerite used for?+

Nickellotharmeyerite is used in collector.

Find nickellotharmeyerite on the map

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