Mitscherlichite is a rare copper-potassium chloride mineral formed as a secondary deposit in volcanic fumaroles. It typically appears as small blue to blue-green prismatic or tabular crystals, often found associated with other chloride minerals in high-temperature volcanic vents.

Hardness

2.5

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent

mineralrare

Mitscherlichite

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

Is this mitscherlichite?

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 mitscherlichite with a known reference. Mitscherlichite sits at Mohs 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: green, green blue.
5
Look at form & habit
Crystal system: tetragonal. Typical habit: crystalline.

Often confused with

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

How to tell apart: Streak differs, so Mitscherlichite leaves white, Tolbachite leaves yellowish red; luster reads vitreous on Mitscherlichite and pearly on Tolbachite.

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Often found alongside mitscherlichite

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

All properties

Chemical formula: K₂CuCl₄·2H₂O
Mohs hardness: 2.5
Density: 2.418 g/cm³
Colors: Green Green blue
Streak: White
Luster: Vitreous
Transparency: Transparent
Crystal system: Tetragonal
Crystal habit: Crystalline
Cleavage: Distinct
Rarity: Rare
Uses: Collector
Host rock: A volcanic sublimate (Vesuvius, Italy); an alteration product of ponomarevite (Tolbachik volcano, Russia)

Where rockhounds find mitscherlichite

Classic worldwide localities

Crater of Vesuvius, Campania, Italy
Tolbachik fissure volcano, Kamchatka Peninsula, Russia

Field-hunting tip

Where it forms: A volcanic sublimate (Vesuvius, Italy); an alteration product of ponomarevite (Tolbachik volcano, Russia). If you start seeing sylvite, metavoltine, gypsum in float, you are in the right ground. Typical habit: crystalline. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify mitscherlichite?+

Mohs hardness is 2.5. Luster: vitreous. The streak is white. Common colors include green, green blue.

Where is mitscherlichite found?+

Notable localities include Crater of Vesuvius, Campania, Italy; Tolbachik fissure volcano, Kamchatka Peninsula, Russia.

Is mitscherlichite safe to handle?+

Mitscherlichite contains copper. Contains copper and chlorine. Handle with care, avoid ingestion or inhalation of dust, and wash hands thoroughly after handling specimens.

What rocks look like mitscherlichite?+

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

What minerals are found with mitscherlichite?+

Mitscherlichite commonly co-occurs with Sylvite, Metavoltine, Gypsum, Ponomarevite, Tolbachite, Dolerophanite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does mitscherlichite form in?+

Where it forms: A volcanic sublimate (Vesuvius, Italy); an alteration product of ponomarevite (Tolbachik volcano, Russia). Working float back to the host body is the standard way to chase a fresh occurrence.

What is mitscherlichite used for?+

Mitscherlichite is used in collector.

Find mitscherlichite on the map

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