Sanguite is a very rare potassium chloride mineral that typically forms as red crusts around volcanic fumaroles. It is named for its blood-red color and is primarily found in the Vesuvius volcanic complex. Collectors should note it is highly water-soluble, similar to sylvite, and requires storage in a humidity-controlled environment.

Hardness

Mohs

Luster

Vitreous

Streak

Reddish orange

Transparency

Transparent

mineralrare

Sanguite

Hardness: ~3
Luster: Vitreous
Streak: Reddish orange
Transparency: Transparent

No image

Is this sanguite?

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 sanguite with a known reference. Sanguite sits at Mohs ~3, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Streak: reddish orange.
3
Read the luster
Hold the specimen under a strong light. Luster: vitreous.
4
Match the color range
Compare against the expected color range: bright red, dark, brownish red with alteration.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: granular, massive, crystalline crusts.

Often confused with

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

mineral

Sylvite

Mohs 2

How to tell apart: Sanguite is noticeably harder (Mohs ~3 vs. 2); streak differs, so Sanguite leaves reddish orange, Sylvite leaves white.

How to tell apart: Streak differs, so Sanguite leaves reddish orange, Halite leaves white.

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Often found alongside sanguite

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

All properties

Chemical formula: KCuCl₃
Mohs hardness: ~3
Density: 2.96 g/cm³
Colors: Bright redDarkBrownish red with alteration
Streak: Reddish orange
Luster: Vitreous
Transparency: Transparent
Crystal system: Monoclinic
Crystal habit: Granular, massive, crystalline crusts
Cleavage: Perfect on {010}, distinct on {102̄}
Rarity: Rare
Uses: Collector
Host rock: As sublimates on scoria around an active fumarole

Where rockhounds find sanguite

Classic worldwide localities

Glavnaya Tenoritovaya (“Major Tenorite”) fumarole, Second scoria cone, Northern Breakthrough of the Great Tolbachik Fissure Eruption, Tolbachik volcano, Kamchatka, Russia

Field-hunting tip

Where it forms: As sublimates on scoria around an active fumarole. If you start seeing belloite, avdoninite, eriochalcite in float, you are in the right ground. Typical habit: granular, massive, crystalline crusts. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify sanguite?+

Mohs hardness is ~3. Luster: vitreous. The streak is reddish orange. Common colors include bright red, dark, brownish red with alteration.

Where is sanguite found?+

Notable localities include Glavnaya Tenoritovaya (“Major Tenorite”) fumarole, Second scoria cone, Northern Breakthrough of the Great Tolbachik Fissure Eruption, Tolbachik volcano, Kamchatka, Russia.

Is sanguite safe to handle?+

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

What rocks look like sanguite?+

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

What minerals are found with sanguite?+

Sanguite commonly co-occurs with Belloite, Avdoninite, Eriochalcite, Sylvite, Halite, Carnallite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does sanguite form in?+

Where it forms: As sublimates on scoria around an active fumarole. Working float back to the host body is the standard way to chase a fresh occurrence.

What is sanguite used for?+

Sanguite is used in collector.

Find sanguite on the map

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