Potassic-jeanlouisite is a rare member of the amphibole supergroup characterized by its high potassium content. It typically forms as small, dark, prismatic crystals within alkaline intrusive complexes and is highly sought after by systematic mineral collectors.
Is this potassic-jeanlouisite?
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 potassic-jeanlouisite with a known reference. Potassic-jeanlouisite sits at Mohs 5-6 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Potassic-jeanlouisite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Potassic-jeanlouisite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: dark brown, black.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: prismatic crystals.
Often confused with
Potassic-jeanlouisite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside potassic-jeanlouisite
Minerals reported to co-occur with potassic-jeanlouisite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- KNa₂Mg₄Fe³⁺Si₈O₂₂(OH)₂
- Mohs hardness
- 5-6
- Density
- 3.31 g/cm³
- Colors
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Prismatic Crystals
- Cleavage
- Perfect Prismatic
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Alkaline Igneous Rocks
- Typical price
- $50-300 per specimen
Where rockhounds find potassic-jeanlouisite
Classic worldwide localities
- Saint-Amable sill, Canada
Field-hunting tip
Look in alkaline igneous rocks country — that is the host setting where potassic-jeanlouisite typically forms. If you start seeing aegirine, nepheline, microcline in float, you are in the right ground. Field specimens usually show a prismatic crystals habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify potassic-jeanlouisite?+
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Find potassic-jeanlouisite on the map
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