Kulkeite is a rare phyllosilicate mineral belonging to the chlorite group, characterized by its regular interstratification of clinochlore and talc layers. It typically appears as white to pale greenish micaceous or platy masses found in high-grade metamorphosed sedimentary environments. Collectors look for these specimens primarily in specific dolomitic marble occurrences where the delicate, pearly lamellae are preserved.
Is this kulkeite?
5-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 kulkeite with a known reference. Kulkeite sits at Mohs ~2, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: white.
- 3Read the lusterHold the specimen under a strong light. Luster: pearly on the cleavage.
- 4Match the color rangeCompare against the expected color range: colorless.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: microscopic crystals.
Often confused with
Kulkeite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside kulkeite
Minerals reported to co-occur with kulkeite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Na₀.₃Mg₈Al(Si,Al)₈O₂₀(OH)₁₀
- Mohs hardness
- ~2
- Density
- 2.7 g/cm³
- Colors
- Streak
- White
- Luster
- Pearly on the cleavage
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Microscopic crystals
- Cleavage
- Perfect on {001}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In dolostone, metamorphosed below 400 ° C, with evaporites
Where rockhounds find kulkeite
Classic worldwide localities
- El Mourdur Hill, near Derrag, 35 km west of Ksar El Boukhari, Tell Atlas Mountains, Algeria
Field-hunting tip
Where it forms: In dolostone, metamorphosed below 400 ° C, with evaporites. If you start seeing talc, chlorite, phlogopite in float, you are in the right ground. Typical habit: microscopic crystals. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify kulkeite?+
Where is kulkeite found?+
What rocks look like kulkeite?+
What minerals are found with kulkeite?+
What kind of rock does kulkeite form in?+
What is kulkeite used for?+
Find kulkeite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
