Bastnäsite-(La) is a rare-earth fluoride carbonate mineral primarily distinguished by its high Lanthanum content. It typically forms hexagonal tabular crystals or granular masses in alkaline igneous rocks and carbonatites, often appearing in brownish or yellowish hues.

Hardness

4-4.5

Mohs

Luster

Vitreous

Streak

White

Transparency

Translucent

mineralrareBastnäsite Group family

Bastnäsite-(La)

Hardness: 4-4.5
Luster: Vitreous
Streak: White
Transparency: Translucent

Is this bastnäsite-(la)?

5-step field check

Run through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.

1
Test the hardness
Try to scratch bastnäsite-(la) with a known reference. Bastnäsite-(La) sits at Mohs 4-4.5 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Bastnäsite-(La) leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Bastnäsite-(La) typically shows a vitreous luster.
4
Match the color range
Compare against the expected color range: yellow, reddish-brown, brown, colorless.
5
Look at form & habit
Crystal system: hexagonal. Typical habit: tabular crystals, massive, granular.

Often confused with

Bastnäsite-(La) vs. its common look-alikes — and how to tell them apart in the field.

Often found alongside bastnäsite-(la)

Minerals reported to co-occur with bastnäsite-(la). Spotting these in float or country rock is a strong cue you are in the right ground.

All properties

Chemical formula: La(CO₃)F
Mohs hardness: 4-4.5
Density: 5.0-5.2 g/cm³
Colors: Yellow Reddish-brown Brown Colorless
Streak: White
Luster: Vitreous
Transparency: Translucent
Crystal system: Hexagonal
Crystal habit: Tabular Crystals, Massive, Granular
Cleavage: Distinct On {1010}
Rarity: Rare
Uses: Collector, Ore of Rare Earth Elements
Host rock: Carbonatites, Rare-earth Element Pegmatites
Typical price: $20-150 for thumbnail specimens

Where rockhounds find bastnäsite-(la)

Classic worldwide localities

Bastnäs, Sweden
Mountain Pass, USA
Bayan Obo, China
Khibiny Massif, Russia

Field-hunting tip

Look in carbonatites, rare-earth element pegmatites country — that is the host setting where bastnäsite-(la) typically forms. If you start seeing allanite, fluorite, barite in float, you are in the right ground. Field specimens usually show a tabular crystals, massive, granular habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify bastnäsite-(la)?+

Mohs hardness is 4-4.5. It typically shows a vitreous luster. The streak is white. Common colors include yellow, reddish-brown, brown, colorless.

Where is bastnäsite-(la) found?+

Notable localities include Bastnäs, Sweden; Mountain Pass, USA; Bayan Obo, China; Khibiny Massif, Russia.

How much is bastnäsite-(la) worth?+

Typical asking prices fall in the range of $20-150 for thumbnail specimens. Quality, size, and provenance can move individual specimens well outside that range.

What rocks look like bastnäsite-(la)?+

Bastnäsite-(La) is most often confused with Bastnäsite-(Ce), Parisite-(Ce), Synchysite-(Ce). A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with bastnäsite-(la)?+

Bastnäsite-(La) commonly co-occurs with Allanite, Fluorite, Barite, Calcite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does bastnäsite-(la) form in?+

Bastnäsite-(La) typically forms in carbonatites, rare-earth element pegmatites. Working float back to the host body is the standard way to chase a fresh occurrence.

What is bastnäsite-(la) used for?+

Bastnäsite-(La) is used in collector, ore of rare earth elements.

Find bastnäsite-(la) on the map

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