Jasmundite is a rare calcium-iron silicate mineral discovered in the combustion metamorphic rocks of the Jasmund cliff on Rügen Island. It typically occurs as minute anhedral grains within rocks formed by the burning of bituminous marls, making it a highly localized curiosity for advanced mineral collectors.

Hardness

3.5

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent

mineralrare

Jasmundite

Hardness: 3.5
Luster: Vitreous
Streak: White
Transparency: Transparent

Is this jasmundite?

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 jasmundite with a known reference. Jasmundite sits at Mohs 3.5 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Jasmundite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Jasmundite typically shows a vitreous luster.
4
Match the color range
Compare against the expected color range: yellow, brownish-yellow.
5
Look at form & habit
Crystal system: tetragonal. Typical habit: anhedral grains.

Often confused with

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

mineral

Larnite

Mohs 6

How to tell apart: Larnite is the harder of the two (Mohs 6 vs. 3.5).

Compare →

Often found alongside jasmundite

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

All properties

Chemical formula: Ca₁₁Fe²⁺(SiO₄)₄(S,OH,Cl)₂
Mohs hardness: 3.5
Density: 2.88 g/cm³
Colors: Yellow Brownish-yellow
Streak: White
Luster: Vitreous
Transparency: Transparent
Crystal system: Tetragonal
Crystal habit: Anhedral Grains
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: Combustion Metamorphic Rocks
Typical price: $50-300 per specimen

Where rockhounds find jasmundite

Classic worldwide localities

Jasmund, Rügen Island, Germany

Field-hunting tip

Look in combustion metamorphic rocks country — that is the host setting where jasmundite typically forms. If you start seeing larnite, portlandite, ettringite in float, you are in the right ground. Field specimens usually show a anhedral grains habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify jasmundite?+

Mohs hardness is 3.5. It typically shows a vitreous luster. The streak is white. Common colors include yellow, brownish-yellow.

Where is jasmundite found?+

Notable localities include Jasmund, Rügen Island, Germany.

How much is jasmundite 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.

What rocks look like jasmundite?+

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

What minerals are found with jasmundite?+

Jasmundite commonly co-occurs with Larnite, Portlandite, Ettringite, Afwillite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does jasmundite form in?+

Jasmundite typically forms in combustion metamorphic rocks. Working float back to the host body is the standard way to chase a fresh occurrence.

What is jasmundite used for?+

Jasmundite is used in collector.

Find jasmundite on the map

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