Trinepheline is a rare orthorhombic polymorph of the common mineral nepheline. It is typically found in alkaline igneous environments and is often difficult to distinguish from common nepheline without advanced X-ray diffraction analysis.
Is this trinepheline?
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 trinepheline with a known reference. Trinepheline sits at Mohs ~5-5.5, 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: vitreous to greasy.
- 4Match the color rangeCompare against the expected color range: white, yellow.
- 5Look at form & habitCrystal system: hexagonal. Typical habit: prismatic crystals.
Often confused with
Trinepheline vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside trinepheline
Minerals reported to co-occur with trinepheline. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- NaAlSiO₄
- Mohs hardness
- ~5-5.5
- Density
- 2.642 g/cm³
- Streak
- White
- Luster
- Vitreous to greasy
- Transparency
- Transparent
- Crystal system
- Hexagonal
- Crystal habit
- Prismatic crystals
- Rarity
- Rare
- Uses
- Collector, Scientific research
- Host rock
- In serpentinized peridotite, replacing jadeite during late stage metamorphism along veins, likely related to decompression
Where rockhounds find trinepheline
Classic worldwide localities
- Tawmaw-Hpakant Jade Tract, Hpakant Township, Mohnyin District, Kachin State, Myanmar
Field-hunting tip
Where it forms: In serpentinized peridotite, replacing jadeite during late stage metamorphism along veins, likely related to decompression. If you start seeing nepheline, fabriesite, banalsite in float, you are in the right ground. Typical habit: prismatic crystals. Train your eye for that shape before scanning the outcrop.
Common questions
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Find trinepheline on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
