Fluormayenite is a rare member of the mayenite supergroup often found in high-temperature contact metamorphic environments. It typically forms small, clear dodecahedral crystals associated with skarn minerals in ejected limestone blocks.

Hardness

5.5-6

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent

mineralrareMayenite Supergroup family

Fluormayenite

Hardness: 5.5-6
Luster: Vitreous
Streak: White
Transparency: Transparent

No image

Is this fluormayenite?

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 fluormayenite with a known reference. Fluormayenite sits at Mohs 5.5-6 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Fluormayenite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Fluormayenite typically shows a vitreous luster.
4
Match the color range
Compare against the expected color range: colorless, white, pale yellow.
5
Look at form & habit
Crystal system: cubic. Typical habit: dodecahedral crystals, massive.

Often confused with

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

Often found alongside fluormayenite

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

All properties

Chemical formula: Ca₁₂Al₁₄O₃₂F₂
Mohs hardness: 5.5-6
Density: 2.7-2.9 g/cm³
Colors: Colorless White Pale Yellow
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 Limestone Xenoliths in Volcanic Rocks
Typical price: $50-300 per specimen

Where rockhounds find fluormayenite

Classic worldwide localities

Bellerberg Volcano, Germany
Chetam Mine, Russia
Kopeysk, Russia

Field-hunting tip

Look in metamorphosed limestone xenoliths in volcanic rocks country — that is the host setting where fluormayenite typically forms. If you start seeing ettringite, gehlenite, periclase 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 fluormayenite?+

Mohs hardness is 5.5-6. It typically shows a vitreous luster. The streak is white. Common colors include colorless, white, pale yellow.

Where is fluormayenite found?+

Notable localities include Bellerberg Volcano, Germany; Chetam Mine, Russia; Kopeysk, Russia.

How much is fluormayenite 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 fluormayenite?+

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

What minerals are found with fluormayenite?+

Fluormayenite commonly co-occurs with Ettringite, Gehlenite, Periclase, Spinels. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does fluormayenite form in?+

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

What is fluormayenite used for?+

Fluormayenite is used in collector, scientific research.

Find fluormayenite on the map

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