Törnebohmite-(La) is a rare silicate mineral belonging to the törnebohmite group, typically found in rare-earth element deposits. It is most frequently encountered as olive-green granular masses associated with other rare-earth minerals like bastnäsite and cerite in skarn environments.
Is this törnebohmite-(la)?
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 törnebohmite-(la) with a known reference. Törnebohmite-(La) sits at Mohs 4.5 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Törnebohmite-(La) leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Törnebohmite-(La) typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: green, yellowish-green, olive-green.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: granular, massive, or small tabular crystals.
Often confused with
Törnebohmite-(La) vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Allanite is the harder of the two (Mohs 5.5-6 vs. 4.5); streak differs — Törnebohmite-(La) leaves white, Allanite leaves gray; luster reads vitreous on Törnebohmite-(La) and submetallic on Allanite.
How to tell apart: Epidote is the harder of the two (Mohs 6-7 vs. 4.5).
How to tell apart: Luster reads vitreous on Törnebohmite-(La) and resinous on Monazite.
Often found alongside törnebohmite-(la)
Minerals reported to co-occur with törnebohmite-(la). Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- La₂Al(SiO₄)₂(OH)
- Mohs hardness
- 4.5
- Density
- 4.8-4.9 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Granular, Massive, Or Small Tabular Crystals
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Rare Earth-rich Skarns and Pegmatites
- Typical price
- $50-300 per specimen
Where rockhounds find törnebohmite-(la)
Classic worldwide localities
- Bastnäs, Sweden
- Khibiny Massif, Russia
- Mountain Pass, California, USA
- Steenkampskraal, South Africa
Field-hunting tip
Look in rare earth-rich skarns and pegmatites country — that is the host setting where törnebohmite-(la) typically forms. If you start seeing bastnäsite, cerite, allanite in float, you are in the right ground. Field specimens usually show a granular, massive, or small tabular crystals habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify törnebohmite-(la)?+
Where is törnebohmite-(la) found?+
How much is törnebohmite-(la) worth?+
What rocks look like törnebohmite-(la)?+
What minerals are found with törnebohmite-(la)?+
What kind of rock does törnebohmite-(la) form in?+
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