Rémondite-(La) is an exceptionally rare rare-earth element carbonate mineral primarily found in the nepheline syenite pegmatites of Mont Saint-Hilaire. Collectors usually seek it in the form of small, tabular, transparent to translucent crystals associated with other rare alkaline-suite minerals.

Hardness

Mohs

Luster

Vitreous

Streak

White

Transparency

Translucent

mineralrareBastnäsite Group family

Rémondite-(La)

Hardness: ~3
Luster: Vitreous
Streak: White
Transparency: Translucent

Is this rémondite-(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 rémondite-(la) with a known reference. Rémondite-(La) sits at Mohs ~3, 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: bright orange yellow.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: irregular grains, microscopic crystals, prismatic.

Often confused with

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

mineral

Bastnäsite

Mohs 4-5

How to tell apart: Bastnäsite is the harder of the two (Mohs 4-5 vs. ~3).

Compare →

Often found alongside rémondite-(la)

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

All properties

Chemical formula: Na₃(La,Ca,Na)₃(CO₃)₅
Mohs hardness: ~3
Density: 3.5 g/cm³
Colors: Bright orange yellow
Streak: White
Luster: Vitreous
Transparency: Translucent
Crystal system: Monoclinic
Crystal habit: Irregular grains, microscopic crystals, prismatic
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: Of late hydrothermal origin, very rare in a small pegmatite in a differentiated alkalic massif

Where rockhounds find rémondite-(la)

Classic worldwide localities

Mt. Koashva, Khibiny massif, Kola Peninsula, Russia

Field-hunting tip

Where it forms: Of late hydrothermal origin, very rare in a small pegmatite in a differentiated alkalic massif. If you start seeing cancrisilite, microcline, sodalite in float, you are in the right ground. Typical habit: irregular grains, microscopic crystals, prismatic. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify rémondite-(la)?+

Mohs hardness is ~3. Luster: vitreous. The streak is white. Common colors include bright orange yellow.

Where is rémondite-(la) found?+

Notable localities include Mt. Koashva, Khibiny massif, Kola Peninsula, Russia.

What rocks look like rémondite-(la)?+

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

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

Rémondite-(La) commonly co-occurs with Cancrisilite, Microcline, Sodalite, Villiaumite, Natrolite, Pectolite. Spotting any of these in float or country rock is a useful trip signal.

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

Where it forms: Of late hydrothermal origin, very rare in a small pegmatite in a differentiated alkalic massif. Working float back to the host body is the standard way to chase a fresh occurrence.

What is rémondite-(la) used for?+

Rémondite-(La) is used in collector.

Find rémondite-(la) on the map

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