Hydroxylbastnäsite-(La) is a rare lanthanum-dominant member of the bastnäsite group characterized by its hexagonal tabular crystal habit. It is typically found in alkaline igneous environments and carbonatites, often associated with other rare-earth-bearing minerals.

Hardness

4-4.5

Mohs

Luster

Vitreous

Streak

White

Transparency

Translucent

mineralrareBastnäsite Group family

Hydroxylbastnäsite-(La)

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

No image

Is this hydroxylbastnäsite-(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 hydroxylbastnäsite-(la) with a known reference. Hydroxylbastnäsite-(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. Streak: white.
3
Read the luster
Hold the specimen under a strong light. Luster: vitreous.
4
Match the color range
Compare against the expected color range: yellow, brownish-yellow, reddish-brown.
5
Look at form & habit
Crystal system: hexagonal. Typical habit: tabular crystals, massive, granular.

Often confused with

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

Often found alongside hydroxylbastnäsite-(la)

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

All properties

Chemical formula: La(CO₃)(OH)
Mohs hardness: 4-4.5
Density: 4.7-4.8 g/cm³
Colors: Yellow Brownish-yellow Reddish-brown
Streak: White
Luster: Vitreous
Transparency: Translucent
Crystal system: Hexagonal
Crystal habit: Tabular crystals, massive, granular
Cleavage: Distinct on {0001}
Rarity: Rare
Uses: Collector
Host rock: alkaline igneous rocks, carbonatites, pegmatites

Where rockhounds find hydroxylbastnäsite-(la)

Classic worldwide localities

Khibiny Massif, Russia
Bayun Obo, China
Mountain Pass, USA
Fen Complex, Norway

Field-hunting tip

Where it forms: alkaline igneous rocks, carbonatites, pegmatites. If you start seeing aegirine, microcline, nepheline in float, you are in the right ground. Typical habit: tabular crystals, massive, granular. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify hydroxylbastnäsite-(la)?+

Mohs hardness is 4-4.5. Luster: vitreous. The streak is white. Common colors include yellow, brownish-yellow, reddish-brown.

Where is hydroxylbastnäsite-(la) found?+

Notable localities include Khibiny Massif, Russia; Bayun Obo, China; Mountain Pass, USA; Fen Complex, Norway.

Is hydroxylbastnäsite-(la) safe to handle?+

Contains minor rare earth elements and thorium impurities which may be radioactive; handle with standard mineral collection precautions and wash hands after handling.

What rocks look like hydroxylbastnäsite-(la)?+

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

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

Hydroxylbastnäsite-(La) commonly co-occurs with Aegirine, Microcline, Nepheline, Fluorite, Barite. Spotting any of these in float or country rock is a useful trip signal.

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

Where it forms: alkaline igneous rocks, carbonatites, pegmatites. Working float back to the host body is the standard way to chase a fresh occurrence.

What is hydroxylbastnäsite-(la) used for?+

Hydroxylbastnäsite-(La) is used in collector.

Find hydroxylbastnäsite-(la) on the map

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