Monazite-(Nd) is a rare earth phosphate mineral characterized by a dominance of neodymium in its composition. It typically occurs as small bright rose-red tabular crystals in pegmatites and is notable for its natural radioactivity due to thorium inclusions.
Is this monazite-(nd)?
5-step field checkRun through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.
- 1Test the hardnessTry to scratch monazite-(nd) with a known reference. Monazite-(Nd) sits at Mohs 5-5.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: grayish white.
- 3Read the lusterHold the specimen under a strong light. Luster: adamantine to resinous.
- 4Match the color rangeCompare against the expected color range: brown, red, yellow, orange.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: crystalline, twinning common.
Often confused with
Monazite-(Nd) vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Luster reads adamantine to resinous on Monazite-(Nd) and resinous, waxy, vitreous to adamantine on Monazite-(Ce).
How to tell apart: Zircon is the harder of the two (Mohs 7.5 vs. 5-5.5); streak differs, so Monazite-(Nd) leaves grayish white, Zircon leaves white; luster reads adamantine to resinous on Monazite-(Nd) and vitreous to adamantine; greasy when metamict on Zircon.
How to tell apart: Streak differs, so Monazite-(Nd) leaves grayish white, Xenotime leaves white; luster reads adamantine to resinous on Monazite-(Nd) and vitreous on Xenotime.
Often found alongside monazite-(nd)
Minerals reported to co-occur with monazite-(nd). Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- NdPO₄
- Mohs hardness
- 5-5.5
- Density
- 4.8-5.5 g/cm³
- Streak
- Grayish white
- Luster
- Adamantine to resinous
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Crystalline, twinning common
- Cleavage
- {100}, distinct; {010}, poor by analogy to monazite-(Ce)
- Rarity
- Rare
- Uses
- Collector, Scientific research
- Host rock
- Granitic pegmatites
Where rockhounds find monazite-(nd)
Classic worldwide localities
- Glogstafel, Val Formazza, on the southeastern slope of Pizzo Cervandone, Alpe Devero, Val d’Aosta, Piedmont, Italy
- Marmara bauxite deposit, Megora, Greece
- Kokšín, near Mítov, Czech Republic
Field-hunting tip
Where it forms: Granitic pegmatites. If you start seeing rutile, xenotime, gadolinite in float, you are in the right ground. Typical habit: crystalline, twinning common. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify monazite-(nd)?+
Where is monazite-(nd) found?+
Is monazite-(nd) safe to handle?+
What rocks look like monazite-(nd)?+
What minerals are found with monazite-(nd)?+
What kind of rock does monazite-(nd) form in?+
What is monazite-(nd) used for?+
Find monazite-(nd) on the map
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