Fluorchegemite is a very rare silicate mineral found in the contact metamorphic zones of volcanic calderas. It is structurally similar to chegemite but distinguished by its fluorine content, typically occurring as small, inconspicuous grains within complex skarn assemblages.
Is this fluorchegemite?
4-step field checkRun through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.
- 1Test the hardnessTry to scratch fluorchegemite with a known reference. Fluorchegemite sits at Mohs 5.5-6, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: white.
- 3Match the color rangeCompare against the expected color range: colorless.
- 4Look at form & habitCrystal system: orthorhombic. Typical habit: anhedral to subhedral grains.
Often confused with
Fluorchegemite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside fluorchegemite
Minerals reported to co-occur with fluorchegemite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ca₇(SiO₄)₃F₂
- Mohs hardness
- 5.5-6
- Density
- 2.91 g/cm³
- Colors
- Streak
- White
- Transparency
- Transparent
- Crystal system
- Orthorhombic
- Crystal habit
- Anhedral to subhedral grains
- Cleavage
- Imperfect on {010}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Formed in the edgrewite-bearing zone of endoskarn (sanidinite facies) at the edge of an altered calciferous xenolith within ignimbrite
Where rockhounds find fluorchegemite
Classic worldwide localities
- Upper Chegem Caldera, Northern Caucasus, Kabardino-Balkaria, Russian, and the Shadil-Khokh volcano, Southern Ossetia, Shida Kartli Region, Georgia
Field-hunting tip
Where it forms: Formed in the edgrewite-bearing zone of endoskarn (sanidinite facies) at the edge of an altered calciferous xenolith within ignimbrite. If you start seeing larnite, edgrewite, wadalite in float, you are in the right ground. Typical habit: anhedral to subhedral grains. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify fluorchegemite?+
Where is fluorchegemite found?+
What rocks look like fluorchegemite?+
What minerals are found with fluorchegemite?+
What kind of rock does fluorchegemite form in?+
What is fluorchegemite used for?+
Find fluorchegemite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
