Arisite-(La) is a rare carbonate mineral discovered in the alkaline pegmatites of the Aris quarries in Namibia. It typically forms delicate, yellow, hexagonal platy crystals that are prized by advanced mineral collectors of rare earth species.

Hardness

3.5

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent

mineralrareArisite Group family

Arisite-(La)

Hardness: 3.5
Luster: Vitreous
Streak: White
Transparency: Transparent

No image

Is this arisite-(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 arisite-(la) with a known reference. Arisite-(La) sits at Mohs 3.5, 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: beige, beige-yellow, pinkish.
5
Look at form & habit
Crystal system: hexagonal. Typical habit: platy crystals.

Often confused with

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

Often found alongside arisite-(la)

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

All properties

Chemical formula: NaLa₂(CO₃)₂[(F₂)₀(CO₃)₁]F
Mohs hardness: 3.5
Density: 4.072 g/cm³
Colors: BeigeBeige-yellowPinkish
Streak: White
Luster: Vitreous
Transparency: Transparent
Crystal system: Hexagonal
Crystal habit: Platy crystals
Cleavage: Poor on {001}
Rarity: Rare
Uses: Collector
Host rock: A late-stage, post-magmatic to hydrothermal mineral in miarolitic cavities as La-rich cores in arisite-(Ce) from phonolite associated with an alkaline volcanic province

Where rockhounds find arisite-(la)

Classic worldwide localities

Ariskop and Railroad (Aris phonolite) quarry, central Namibia

Field-hunting tip

Where it forms: A late-stage, post-magmatic to hydrothermal mineral in miarolitic cavities as La-rich cores in arisite-(Ce) from phonolite associated with an alkaline volcanic province. If you start seeing villiaumite, aegirine, analcime in float, you are in the right ground. Typical habit: platy crystals. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify arisite-(la)?+

Mohs hardness is 3.5. Luster: vitreous. The streak is white. Common colors include beige, beige-yellow, pinkish.

Where is arisite-(la) found?+

Notable localities include Ariskop and Railroad (Aris phonolite) quarry, central Namibia.

What rocks look like arisite-(la)?+

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

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

Arisite-(La) commonly co-occurs with Villiaumite, Aegirine, Analcime, Apatite, Fluorite, Manganoneptunite. Spotting any of these in float or country rock is a useful trip signal.

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

Where it forms: A late-stage, post-magmatic to hydrothermal mineral in miarolitic cavities as La-rich cores in arisite-(Ce) from phonolite associated with an alkaline volcanic province. Working float back to the host body is the standard way to chase a fresh occurrence.

What is arisite-(la) used for?+

Arisite-(La) is used in collector.

Find arisite-(la) on the map

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