Niobophyllite is a rare member of the astrophyllite group, distinguished primarily by its high niobium content. It forms distinct golden-bronze bladed or star-shaped aggregates, often found embedded in alkaline igneous rocks. Collectors prize it for its unique habit and similarity to the more common astrophyllite.
Is this niobophyllite?
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 niobophyllite with a known reference. Niobophyllite sits at Mohs 3 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Niobophyllite leaves a yellowish-brown streak.
- 3Read the lusterHold the specimen under a strong light. Niobophyllite typically shows a pearly luster.
- 4Match the color rangeCompare against the expected color range: bronze-brown, golden-brown, dark brown.
- 5Look at form & habitCrystal system: triclinic. Typical habit: bladed, platy, radiating or stellate aggregates.
Often confused with
Niobophyllite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Streak differs — Niobophyllite leaves yellowish-brown, Astrophyllite leaves golden-brown; luster reads pearly on Niobophyllite and submetallic on Astrophyllite.
How to tell apart: Streak differs — Niobophyllite leaves yellowish-brown, Kupletskite leaves brown; luster reads pearly on Niobophyllite and submetallic on Kupletskite.
Often found alongside niobophyllite
Minerals reported to co-occur with niobophyllite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (K,Na)₃(Fe,Mn)₇(Nb,Ti)₂Si₈O₂₆(OH)₄F
- Mohs hardness
- 3
- Density
- 3.37 g/cm³
- Streak
- Yellowish-brown
- Luster
- Pearly
- Transparency
- Translucent
- Crystal system
- Triclinic
- Crystal habit
- Bladed, Platy, Radiating or Stellate Aggregates
- Cleavage
- Perfect On {001}
- Rarity
- Rare
- Uses
- Collector, Scientific Research
- Host rock
- Alkaline Igneous Rocks, Pegmatites
- Typical price
- $20-150 per specimen depending on size and crystal quality
Where rockhounds find niobophyllite
Classic worldwide localities
- Kola Peninsula, Russia
- Mont Saint-Hilaire, Canada
- Greenland
Field-hunting tip
Look in alkaline igneous rocks, pegmatites country — that is the host setting where niobophyllite typically forms. If you start seeing aegirine, microcline, nepheline in float, you are in the right ground. Field specimens usually show a bladed, platy, radiating or stellate aggregates habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find niobophyllite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
