Bornemanite is a rare sodium-titanium-niobium silicate phosphate found almost exclusively in the alkaline massifs of the Kola Peninsula. It typically occurs as distinct yellow-brown platy crystals or as intergrowths within complex pegmatite zones. Collectors prize it as a rare member of the lamprophyllite group, often requiring mineral analysis for definitive identification due to its similarity to other complex silicates.
Is this bornemanite?
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 bornemanite with a known reference. Bornemanite sits at Mohs 3.5-4, 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: pearly.
- 4Match the color rangeCompare against the expected color range: light yellow.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: aggregates, platy.
Often confused with
Bornemanite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Bornemanite leaves white, Lamprophyllite leaves pale yellow, may have an orange tint; luster reads pearly on Bornemanite and submetallic on cleavages on Lamprophyllite.
How to tell apart: Streak differs, so Bornemanite leaves white, Lomonosovite leaves light rose-cinnamon; luster reads pearly on Bornemanite and vitreous to adamantine on cleavages, greasy on fractures on Lomonosovite.
Often found alongside bornemanite
Minerals reported to co-occur with bornemanite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Na₆(Na□)Ba₂Ti₂Nb₂(Na₅□)Ti₂(Si₂O₇)₄(PO₄)₂O₄(OH)₂F₂
- Mohs hardness
- 3.5-4
- Density
- 3.47-3.50 g/cm³
- Colors
- Streak
- White
- Luster
- Pearly
- Transparency
- Translucent to transparent
- Crystal system
- Orthorhombic
- Crystal habit
- Aggregates, platy
- Cleavage
- Perfect on {001}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In the natrolite zone of alkalic pegmatites in a differentiated alkalic massif
Where rockhounds find bornemanite
Classic worldwide localities
- Jubilee pegmatite, on Mt. Karnasurt, and on Mt. Alluaiv, Lovozero massif, Kola Peninsula, Russia
Field-hunting tip
Where it forms: In the natrolite zone of alkalic pegmatites in a differentiated alkalic massif. If you start seeing natrolite, lomonosovite in float, you are in the right ground. Typical habit: aggregates, platy. Train your eye for that shape before scanning the outcrop.
Common questions
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Find bornemanite on the map
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