Nickelpicromerite is a rare secondary sulfate mineral occurring as efflorescences or crusts in the oxidized zones of nickel-rich ore deposits. It is best identified by its vibrant green color and association with other nickel sulfates in mine workings. Collectors typically seek out well-formed micro-specimens from historic European mining districts.

Hardness

2-2.5

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent

mineralrarePicromerite Group family

Nickelpicromerite

Hardness: 2-2.5
Luster: Vitreous
Streak: White
Transparency: Transparent

Is this nickelpicromerite?

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 nickelpicromerite with a known reference. Nickelpicromerite sits at Mohs 2-2.5, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Streak: white.
3
Read the luster
Hold the specimen under a strong light. Luster: vitreous.
4
Match the color range
Compare against the expected color range: light greenish blue.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: crusts, granular, prismatic crystals.

Often confused with

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

Often found alongside nickelpicromerite

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

All properties

Chemical formula: K₂Ni(SO₄)₂·6H₂O
Mohs hardness: 2-2.5
Density: 2.20 g/cm³
Colors: Light greenish blue
Streak: White
Luster: Vitreous
Transparency: Transparent
Crystal system: Monoclinic
Crystal habit: Crusts, granular, prismatic crystals
Cleavage: Distinct on {102̄} (by analogy to picromerite)
Rarity: Rare
Uses: Collector
Host rock: A secondary mineral in the fractures of slightly weathered actinolite-talc schist containing partially vermiculitized biotite and partially altered, nickle-bearing sulfides

Where rockhounds find nickelpicromerite

Classic worldwide localities

Chelyabinsk area, South Urals, Russia

Field-hunting tip

Where it forms: A secondary mineral in the fractures of slightly weathered actinolite-talc schist containing partially vermiculitized biotite and partially altered, nickle-bearing sulfides. If you start seeing gypsum, goethite in float, you are in the right ground. Typical habit: crusts, granular, prismatic crystals. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify nickelpicromerite?+

Mohs hardness is 2-2.5. Luster: vitreous. The streak is white. Common colors include light greenish blue.

Where is nickelpicromerite found?+

Notable localities include Chelyabinsk area, South Urals, Russia.

Is nickelpicromerite safe to handle?+

Nickelpicromerite contains nickel. Wash your hands afterwards, never grind or breathe the dust, and store it apart from specimens you handle often.

What rocks look like nickelpicromerite?+

Nickelpicromerite is most often confused with Picromerite, Goslarite, Melanterite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with nickelpicromerite?+

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

What kind of rock does nickelpicromerite form in?+

Where it forms: A secondary mineral in the fractures of slightly weathered actinolite-talc schist containing partially vermiculitized biotite and partially altered, nickle-bearing sulfides. Working float back to the host body is the standard way to chase a fresh occurrence.

What is nickelpicromerite used for?+

Nickelpicromerite is used in collector.

Find nickelpicromerite on the map

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