Monazite-(La) is a rare-earth phosphate mineral often found as small, wedge-shaped brownish crystals in pegmatites. Collectors should look for its characteristic resinous luster and distinct crystal habits, though it is frequently identified through X-ray diffraction due to its similarity to other rare-earth minerals. Always handle with care due to its inherent radioactivity from thorium content.

Hardness

5-5.5

Mohs

Luster

Resinous

Streak

White

Transparency

Translucent

mineraluncommonMonazite Group family

Monazite-(La)

Hardness: 5-5.5
Luster: Resinous
Streak: White
Transparency: Translucent

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

Often confused with

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

mineral

Zircon

Mohs 7.5

How to tell apart: Zircon is the harder of the two (Mohs 7.5 vs. 5-5.5); luster reads resinous on Monazite-(La) and adamantine on Zircon.

How to tell apart: Luster reads resinous on Monazite-(La) and adamantine on Titanite.

How to tell apart: Luster reads resinous on Monazite-(La) and vitreous on Xenotime.

Compare →

Often found alongside monazite-(la)

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

All properties

Chemical formula: (La,Ce,Nd)PO₄
Mohs hardness: 5-5.5
Density: 4.8-5.3 g/cm³
Colors: Yellowish-brown Reddish-brown Brown Yellow
Streak: White
Luster: Resinous
Transparency: Translucent
Crystal system: Monoclinic
Crystal habit: Tabular Crystals, Wedge-shaped Crystals, Granular
Cleavage: Distinct On {100}
Rarity: Uncommon
Uses: Collector, Ore of Rare Earth Elements
Host rock: Granite Pegmatites, Granitic Gneiss, Carbonatites
Typical price: $10-100 per specimen

Where rockhounds find monazite-(la)

Classic worldwide localities

Madagascar
Brazil
India
United States
Norway

Field-hunting tip

Look in granite pegmatites, granitic gneiss, carbonatites country — that is the host setting where monazite-(la) typically forms. If you start seeing quartz, feldspar, biotite in float, you are in the right ground. Field specimens usually show a tabular crystals, wedge-shaped crystals, granular habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify monazite-(la)?+

Mohs hardness is 5-5.5. It typically shows a resinous luster. The streak is white. Common colors include yellowish-brown, reddish-brown, brown, yellow.

Where is monazite-(la) found?+

Notable localities include Madagascar; Brazil; India; United States; Norway.

How much is monazite-(la) worth?+

Typical asking prices fall in the range of $10-100 per specimen. Quality, size, and provenance can move individual specimens well outside that range.

Is monazite-(la) safe to handle?+

This mineral is radioactive. Monazite contains thorium and/or uranium impurities, making it weakly radioactive; wash hands after handling and avoid inhaling dust. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like monazite-(la)?+

Monazite-(La) is most often confused with Zircon, Titanite, Xenotime. A quick hardness test and a streak check separate the look-alikes faster than color alone.

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

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

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

Monazite-(La) typically forms in granite pegmatites, granitic gneiss, carbonatites. Working float back to the host body is the standard way to chase a fresh occurrence.

What is monazite-(la) used for?+

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

Find monazite-(la) on the map

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