Maghagendorfite is a rare phosphate mineral member of the Alluaudite group, primarily occurring as a secondary mineral in complex granite pegmatites. Collectors look for its characteristic yellowish-brown hues, often found as granular aggregates or alteration crusts surrounding primary phosphate minerals like triphylite.
Is this maghagendorfite?
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 maghagendorfite with a known reference. Maghagendorfite sits at Mohs 3.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: gray green.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: greenish black.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: granular masses, crusts, or rare prismatic crystals.
Often confused with
Maghagendorfite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Alluaudite is the harder of the two (Mohs 5-5.5 vs. 3.5); streak differs, so Maghagendorfite leaves gray green, Alluaudite leaves dirty yellow.
How to tell apart: Streak differs, so Maghagendorfite leaves gray green, Triphylite leaves white to grayish white.
Often found alongside maghagendorfite
Minerals reported to co-occur with maghagendorfite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Na₂MgFeFe(PO₄)₃
- Mohs hardness
- 3.5
- Density
- 3.4-3.5 g/cm³
- Colors
- Streak
- Gray green
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Granular masses, crusts, or rare prismatic crystals
- Cleavage
- Good on {001}; poor on {110} (by analogy to hagendorfite)
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In a complex zoned granite pegmatite
Where rockhounds find maghagendorfite
Classic worldwide localities
- Dyke Lode, near Custer, Custer Co., South Dakota, USA
- Rapid Creek, Yukon Territory, Canada
Field-hunting tip
Where it forms: In a complex zoned granite pegmatite. If you start seeing hagendorfite in float, you are in the right ground. Typical habit: granular masses, crusts, or rare prismatic crystals. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify maghagendorfite?+
Where is maghagendorfite found?+
What rocks look like maghagendorfite?+
What minerals are found with maghagendorfite?+
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Find maghagendorfite on the map
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