Natrophilite is a rare phosphate mineral primarily found in complex granite pegmatites. It is typically identified through its yellow to brownish massive form and is often studied for its structural relationship with other members of the triphylite group.
Is this natrophilite?
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 natrophilite with a known reference. Natrophilite sits at Mohs 4.5-5, 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: bright resinous to nearly adamantine, somewhat pearly on the {001} cleavage.
- 4Match the color rangeCompare against the expected color range: yellow.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: massive.
Often confused with
Natrophilite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Luster reads bright resinous to nearly adamantine, somewhat pearly on the {001} cleavage on Natrophilite and vitreous to subresinous on Triphylite.
How to tell apart: Luster reads bright resinous to nearly adamantine, somewhat pearly on the {001} cleavage on Natrophilite and vitreous to subresinous on Lithiophilite.
Often found alongside natrophilite
Minerals reported to co-occur with natrophilite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- NaMnPO₄
- Mohs hardness
- 4.5-5
- Density
- 3.41 g/cm³
- Colors
- Streak
- White
- Luster
- Bright resinous to nearly adamantine, somewhat pearly on the {001} cleavage
- Transparency
- Transparent to translucent
- Crystal system
- Orthorhombic
- Crystal habit
- Massive
- Cleavage
- {001}, good; {100}, indistinct; {210}, interrupted
- Rarity
- Rare
- Uses
- Collector, Reference material
- Host rock
- A rare mineral, replacing lithiophilite, in a complex granite pegmatite
Where rockhounds find natrophilite
Classic worldwide localities
- Branchville, Fairfield Co., Connecticut, USA
Field-hunting tip
Where it forms: A rare mineral, replacing lithiophilite, in a complex granite pegmatite. If you start seeing lithiophilite, triploidite, eosphorite in float, you are in the right ground. Typical habit: massive. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify natrophilite?+
Where is natrophilite found?+
What rocks look like natrophilite?+
What minerals are found with natrophilite?+
What kind of rock does natrophilite form in?+
What is natrophilite used for?+
Find natrophilite on the map
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