Chlormayenite is a rare mineral found primarily in contact metamorphosed limestone xenoliths. It typically occurs as small, colorless to yellowish dodecahedral crystals and is scientifically significant for its structural relationship to mayenite and potential industrial applications in cement chemistry.

Hardness

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent

mineralrareMayenite Group family

Chlormayenite

Hardness: 6
Luster: Vitreous
Streak: White
Transparency: Transparent

Is this chlormayenite?

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 chlormayenite with a known reference. Chlormayenite sits at Mohs 6 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Chlormayenite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Chlormayenite typically shows a vitreous luster.
4
Match the color range
Compare against the expected color range: colorless, white, yellowish.
5
Look at form & habit
Crystal system: cubic. Typical habit: dodecahedral crystals, massive.

Often confused with

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

Often found alongside chlormayenite

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

All properties

Chemical formula: Ca₁₂Al₁₄O₃₂Cl₂
Mohs hardness: 6
Density: 2.68 g/cm³
Colors: Colorless White Yellowish
Streak: White
Luster: Vitreous
Transparency: Transparent
Crystal system: Cubic
Crystal habit: Dodecahedral Crystals, Massive
Cleavage: None
Rarity: Rare
Uses: Collector, Scientific Research
Host rock: Metamorphosed Carbonate Xenoliths in Volcanic Rocks
Typical price: $50-300 per specimen

Where rockhounds find chlormayenite

Classic worldwide localities

Bellerberg Volcano (Germany)
Etna (Italy)
Hatrurim Formation (Israel)

Field-hunting tip

Look in metamorphosed carbonate xenoliths in volcanic rocks country — that is the host setting where chlormayenite typically forms. If you start seeing ettringite, portlandite, calcite in float, you are in the right ground. Field specimens usually show a dodecahedral crystals, massive habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify chlormayenite?+

Mohs hardness is 6. It typically shows a vitreous luster. The streak is white. Common colors include colorless, white, yellowish.

Where is chlormayenite found?+

Notable localities include Bellerberg Volcano (Germany); Etna (Italy); Hatrurim Formation (Israel).

How much is chlormayenite 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 chlormayenite?+

Chlormayenite is most often confused with Grossularite Garnet, Gehlenite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with chlormayenite?+

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

What kind of rock does chlormayenite form in?+

Chlormayenite typically forms in metamorphosed carbonate xenoliths in volcanic rocks. Working float back to the host body is the standard way to chase a fresh occurrence.

What is chlormayenite used for?+

Chlormayenite is used in collector, scientific research.

Find chlormayenite on the map

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