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 6, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: faint brown.
- 3Read the lusterHold the specimen under a strong light. Luster: resinous to dull.
- 4Match the color rangeCompare against the expected color range: reddish brown, black.
- 5Look at form & habitCrystal system: hexagonal. Typical habit: massive, prismatic.
Often confused with
Britholite-(Y) vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Britholite-(Y) is noticeably harder (Mohs 6 vs. 5); 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.
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
- Ca₂Y₃(SiO₄)₃OH
- Mohs hardness
- 6
- Density
- 4.35 g/cm³
- Colors
- Streak
- Faint brown
- Luster
- Resinous to dull
- Transparency
- Translucent to transparent
- Crystal system
- Hexagonal
- Crystal habit
- Massive, prismatic
- Cleavage
- Imperfect on {0001}, {1010}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In pegmatites
Where rockhounds find britholite-(y)
Classic worldwide localities
- Suishoyama pegmatite, near Iisaka, Fukushima Prefecture, and from Shinden, Gifu Prefecture, Japan
Field-hunting tip
Where it forms: In pegmatites. If you start seeing yttrialite, thorogummite, tengerite in float, you are in the right ground. Typical habit: massive, prismatic. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify britholite-(y)?+
Where is britholite-(y) found?+
Is britholite-(y) safe to handle?+
What rocks look like britholite-(y)?+
What minerals are found with britholite-(y)?+
What kind of rock does britholite-(y) form in?+
What is britholite-(y) used for?+
Find britholite-(y) on the map
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