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, 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.