Britholite-(Y) is a rare earth-bearing silicate mineral belonging to the apatite supergroup. It is typically found in alkaline igneous environments as opaque, brownish, prismatic crystals or massive aggregates that are often slightly radioactive due to thorium content.
Is this britholite-(y)?
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 britholite-(y) with a known reference. Britholite-(Y) 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. Britholite-(Y) leaves a faint brown streak.
- 3Read the lusterHold the specimen under a strong light. Britholite-(Y) typically shows a resinous to dull luster.
- 4Match the color rangeCompare against the expected color range: brown, yellow, gray, white.
- 5Look at form & habitCrystal system: hexagonal. Typical habit: prismatic crystals, massive.
Often confused with
Britholite-(Y) vs. its common look-alikes, and how to tell them apart in the field.

How to tell apart: Streak differs, so Britholite-(Y) leaves faint brown, Apatite leaves white; luster reads resinous to dull on Britholite-(Y) and vitreous on Apatite.

How to tell apart: Streak differs, so Britholite-(Y) leaves faint brown, Allanite leaves gray; luster reads resinous to dull on Britholite-(Y) and submetallic on Allanite.

How to tell apart: Streak differs, so Britholite-(Y) leaves faint brown, Monazite leaves white; luster reads resinous to dull on Britholite-(Y) and resinous on Monazite.
Often found alongside britholite-(y)
Minerals reported to co-occur with britholite-(y). Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (Y,Ca,Ln)₅(SiO₄,PO₄)₃(OH,F)
- Mohs hardness
- 5-5.5
- Density
- 4.2-4.5 g/cm³
- Streak
- Faint Brown
- Luster
- Resinous to Dull
- Transparency
- Translucent
- Crystal system
- Hexagonal
- Crystal habit
- Prismatic Crystals, Massive
- Cleavage
- Imperfect On {0001}, {1010}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Alkaline Igneous Rocks, Pegmatites
Where rockhounds find britholite-(y)
Classic worldwide localities
- Kola Peninsula, Russia
- Mont Saint-Hilaire, Canada
- Ilimaussaq complex, Greenland
- Norra Kärr, Sweden
Field-hunting tip
Look in alkaline igneous rocks, pegmatites country, the host setting where britholite-(y) typically forms. If you start seeing aegirine, eudialyte, microcline in float, you are in the right ground. Field specimens usually show a prismatic crystals, massive habit, so train your eye for that shape before scanning the outcrop.




