Rhabdophane-(Y) is a rare yttrium phosphate mineral that typically forms as delicate, radiating fibrous coatings or crusts. It is most often found as a secondary mineral in oxidized zones of pegmatites or hydrothermal environments. Collectors prize its unique, soft luster and complex chemical composition.
Is this rhabdophane-(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 rhabdophane-(y) with a known reference. Rhabdophane-(Y) sits at Mohs 3.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: yellowish white.
- 3Read the lusterHold the specimen under a strong light. Luster: silky to dull.
- 4Match the color rangeCompare against the expected color range: yellowish white, yellowish brown.
- 5Look at form & habitCrystal system: hexagonal. Typical habit: crusts, globular, radiating fibrous aggregates.
Often confused with
Rhabdophane-(Y) vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Rhabdophane-(Y) leaves yellowish white, Rhabdophane-(Ce) leaves white; luster reads silky to dull on Rhabdophane-(Y) and greasy to dull on Rhabdophane-(Ce).
How to tell apart: Streak differs, so Rhabdophane-(Y) leaves yellowish white, Churchite-(Y) leaves white; luster reads silky to dull on Rhabdophane-(Y) and vitreous, pearly on cleavages on Churchite-(Y).
How to tell apart: Monazite is the harder of the two (Mohs 5-5.5 vs. 3.5); streak differs, so Rhabdophane-(Y) leaves yellowish white, Monazite leaves white; luster reads silky to dull on Rhabdophane-(Y) and resinous on Monazite.
Often found alongside rhabdophane-(y)
Minerals reported to co-occur with rhabdophane-(y). Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- YPO₄·H₂O
- Mohs hardness
- 3.5
- Density
- 4.54 g/cm³
- Streak
- Yellowish white
- Luster
- Silky to dull
- Transparency
- Translucent
- Crystal system
- Hexagonal
- Crystal habit
- Crusts, globular, radiating fibrous aggregates
- Rarity
- Rare
- Uses
- Collector, Scientific research
- Host rock
- Forms druses on alkaline olivine basalt
Where rockhounds find rhabdophane-(y)
Classic worldwide localities
- Higashimatsuura alkaline olivine basalt, Hinodematsu, Genkai-cho, Saga Prefecture, Japan
Field-hunting tip
Where it forms: Forms druses on alkaline olivine basalt. If you start seeing plagioclase, forsterite, augite in float, you are in the right ground. Typical habit: crusts, globular, radiating fibrous aggregates. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify rhabdophane-(y)?+
Where is rhabdophane-(y) found?+
Is rhabdophane-(y) safe to handle?+
What rocks look like rhabdophane-(y)?+
What minerals are found with rhabdophane-(y)?+
What kind of rock does rhabdophane-(y) form in?+
What is rhabdophane-(y) used for?+
Find rhabdophane-(y) on the map
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