Jahnsite-(CaMnMn) is a rare phosphate mineral typically found in complex granite pegmatites as a late-stage alteration product. It is primarily sought after by advanced collectors for its aesthetic small, amber-colored crystals that form in vugs alongside other rarer phosphate species.
Is this jahnsite-(camnmn)?
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 jahnsite-(camnmn) with a known reference. Jahnsite-(CaMnMn) sits at Mohs 3-4 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Jahnsite-(CaMnMn) leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Jahnsite-(CaMnMn) typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: yellow, yellowish-brown, brown.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: tabular to prismatic crystals, often as drusy coatings or small clusters.
Often confused with
Jahnsite-(CaMnMn) vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Streak differs — Jahnsite-(CaMnMn) leaves white, Rockbridgeite leaves greenish-brown.
How to tell apart: Jahnsite-(CaMnMn) is noticeably harder (Mohs 3-4 vs. 1.5-2); streak differs — Jahnsite-(CaMnMn) leaves white, Vivianite leaves white to light blue.
Often found alongside jahnsite-(camnmn)
Minerals reported to co-occur with jahnsite-(camnmn). Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- CaMn²⁺Mn²⁺₂Fe³⁺₂ (PO₄)₄(OH)₂·8H₂O
- Mohs hardness
- 3-4
- Density
- 2.7-2.9 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Tabular to Prismatic Crystals, Often as Drusy Coatings or Small Clusters
- Cleavage
- Distinct On {001}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Phosphate-rich Granite Pegmatites
- Typical price
- $50-300 per specimen depending on crystal size and matrix quality
Where rockhounds find jahnsite-(camnmn)
Classic worldwide localities
- Tip Top mine, South Dakota, USA
- Palermo #1 mine, New Hampshire, USA
- Mangualde, Portugal
- Hagendorf, Germany
Field-hunting tip
Look in phosphate-rich granite pegmatites country — that is the host setting where jahnsite-(camnmn) typically forms. If you start seeing triphylite, fairfieldite, apatite in float, you are in the right ground. Field specimens usually show a tabular to prismatic crystals, often as drusy coatings or small clusters habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify jahnsite-(camnmn)?+
Where is jahnsite-(camnmn) found?+
How much is jahnsite-(camnmn) worth?+
What rocks look like jahnsite-(camnmn)?+
What minerals are found with jahnsite-(camnmn)?+
What kind of rock does jahnsite-(camnmn) form in?+
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Find jahnsite-(camnmn) on the map
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