Natrophosphate is an exceptionally rare and highly water-soluble mineral typically found in hyperalkaline igneous complexes. It forms clear to white crystals that are prone to dehydration and deliquescence, requiring storage in sealed containers to prevent damage from atmospheric moisture.
Is this natrophosphate?
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 natrophosphate with a known reference. Natrophosphate sits at Mohs 1-2.5, 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: vitreous to greasy, waxy to frosty on exposure.
- 4Match the color rangeCompare against the expected color range: colorless, white.
- 5Look at form & habitCrystal system: cubic. Typical habit: fibrous, radial.
Often confused with
Natrophosphate vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside natrophosphate
Minerals reported to co-occur with natrophosphate. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Na₇(PO₄)₂F·19H₂O
- Mohs hardness
- 1-2.5
- Density
- 1.71-1.72 g/cm³
- Streak
- White
- Luster
- Vitreous to greasy, waxy to frosty on exposure
- Transparency
- Transparent to translucent
- Crystal system
- Cubic
- Crystal habit
- Fibrous, radial
- Cleavage
- On {111}, imperfect, in slightly altered specimens
- Fluorescence
- Weak orange under SW and LW UV
- Rarity
- Rare
- Uses
- Collector
- Host rock
- A rare mineral in ijolite-urtite pegmatite in a differentiated alkaline massif (Kola Peninsula, Russia); in sodalite xenoliths in an intrusive alkalic gabbro-syenite complex (Mont Saint-Hilaire, Canada)
Where rockhounds find natrophosphate
Classic worldwide localities
- Mts. Yukspor and Koashva, Khibiny massif, and Mts. Karnasurt and Alluaiv, Lovozero massif, Kola Peninsula, Russia
- Mont Saint-Hilaire, Quebec, Canada
- Aris quarry, about 25 km south of Windhoek, Namibia
Field-hunting tip
Where it forms: A rare mineral in ijolite-urtite pegmatite in a differentiated alkaline massif (Kola Peninsula, Russia); in sodalite xenoliths in an intrusive alkalic gabbro-syenite complex (Mont Saint-Hilaire, Canada). If you start seeing villiaumite, aegirine, delhayelite in float, you are in the right ground. Typical habit: fibrous, radial. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify natrophosphate?+
Where is natrophosphate found?+
What rocks look like natrophosphate?+
What minerals are found with natrophosphate?+
What kind of rock does natrophosphate form in?+
What is natrophosphate used for?+
Find natrophosphate on the map
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