Allanite-(La) is a member of the epidote group, characterized by high lanthanum content and structural thorium. It is typically found as dark, opaque, prismatic crystals that often exhibit a pitch-like luster when fresh, though it is frequently found in a metamict state due to its radioactivity.

Hardness

5.5-6

Mohs

Luster

Vitreous

Streak

Grey

Transparency

Opaque

mineralrareEpidote Group family

Allanite-(La)

Hardness: 5.5-6
Luster: Vitreous
Streak: Grey
Transparency: Opaque

Is this allanite-(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 allanite-(la) with a known reference. Allanite-(La) sits at Mohs 5.5-6 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Allanite-(La) leaves a grey streak.
3
Read the luster
Hold the specimen under a strong light. Allanite-(La) typically shows a vitreous luster.
4
Match the color range
Compare against the expected color range: black, brown, reddish-brown.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: prismatic crystals, tabular, massive, granular.

Often confused with

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

mineral

Epidote

Mohs 6-7

How to tell apart: Streak differs — Allanite-(La) leaves grey, Epidote leaves white.

How to tell apart: Streak differs — Allanite-(La) leaves grey, Allanite-(Ce) leaves greyish-white; luster reads vitreous on Allanite-(La) and submetallic on Allanite-(Ce).

How to tell apart: Streak differs — Allanite-(La) leaves grey, Allanite leaves gray; luster reads vitreous on Allanite-(La) and submetallic on Allanite.

Compare →

Often found alongside allanite-(la)

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

All properties

Chemical formula: (La,Ca,Ce,Th)₂(Al,Fe³⁺,Fe²⁺)₃(SiO₄)₃(OH)
Mohs hardness: 5.5-6
Density: 3.5-4.2 g/cm³
Colors: Black Brown Reddish-brown
Streak: Grey
Luster: Vitreous
Transparency: Opaque
Crystal system: Monoclinic
Crystal habit: Prismatic Crystals, Tabular, Massive, Granular
Cleavage: Poor
Rarity: Rare
Uses: Collector
Host rock: Granite Pegmatites, Syenites, Contact Metamorphosed Limestones
Typical price: $20-150 per specimen depending on crystal size and quality

Where rockhounds find allanite-(la)

Classic worldwide localities

Madagascar
Norway
USA (New Jersey)
Canada (Quebec)
China

Field-hunting tip

Look in granite pegmatites, syenites, contact metamorphosed limestones country — that is the host setting where allanite-(la) typically forms. If you start seeing feldspar, quartz, biotite in float, you are in the right ground. Field specimens usually show a prismatic crystals, tabular, massive, granular habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify allanite-(la)?+

Mohs hardness is 5.5-6. It typically shows a vitreous luster. The streak is grey. Common colors include black, brown, reddish-brown.

Where is allanite-(la) found?+

Notable localities include Madagascar; Norway; USA (New Jersey); Canada (Quebec); China.

How much is allanite-(la) worth?+

Typical asking prices fall in the range of $20-150 per specimen depending on crystal size and quality. Quality, size, and provenance can move individual specimens well outside that range.

Is allanite-(la) safe to handle?+

This mineral is radioactive. Due to the presence of Thorium in its structure, this mineral is weakly radioactive and should be handled with care; wash hands after handling and avoid inhaling dust. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like allanite-(la)?+

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

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

Allanite-(La) commonly co-occurs with Feldspar, Quartz, Biotite, Titanite, Zircon. Spotting any of these in float or country rock is a useful trip signal.

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

Allanite-(La) typically forms in granite pegmatites, syenites, contact metamorphosed limestones. Working float back to the host body is the standard way to chase a fresh occurrence.

What is allanite-(la) used for?+

Allanite-(La) is used in collector.

Find allanite-(la) on the map

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