Jörgkellerite is a rare sodium manganese phosphate, typically brown. It is a product of low-temperature, oxidative alteration of gregoryite-nyerereite carbonatitic lavas. Associated minerals include fluorite, khanneshite and barite. It was first described from Oldoinyo Lengai volcano, Gregory Rift, northern Tanzania.
Is this jörgkellerite?
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 jörgkellerite with a known reference. Jörgkellerite sits at Mohs 3, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Jörgkellerite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Jörgkellerite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: brown.
- 5Look at form & habitCrystal system: hexagonal. Typical habit: tabular crystals, clusters.
Often confused with
Jörgkellerite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside jörgkellerite
Minerals reported to co-occur with jörgkellerite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Na₃Mn³⁺₃(PO₄)₂(CO₃)O₂·5H₂O
- Mohs hardness
- 3
- Density
- 2.56 g/cm³
- Colors
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Hexagonal
- Crystal habit
- Tabular Crystals, Clusters
- Cleavage
- Perfect On {001}, Micaceous
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Alkaline Pegmatites
Where rockhounds find jörgkellerite
Classic worldwide localities
- Oldoinyo Lengai volcano, Gregory Rift, northern Tanzania
Field-hunting tip
Look in alkaline pegmatites country, the host setting where jörgkellerite typically forms. If you start seeing aegirine, microcline, nepheline in float, you are in the right ground. Field specimens usually show a tabular crystals, clusters habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify jörgkellerite?+
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What rocks look like jörgkellerite?+
What minerals are found with jörgkellerite?+
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Find jörgkellerite on the map
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