Rhabdophane-(La) is a rare secondary phosphate mineral typically found as dull crusts or botryoidal coatings on other minerals. It is often a weathering product of primary rare-earth phosphates like monazite and is best identified by its association with altered radioactive mineral assemblages.
Is this rhabdophane-(la)?
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-(la) with a known reference. Rhabdophane-(La) sits at Mohs 3-3.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: white.
- 3Read the lusterHold the specimen under a strong light. Luster: greasy to silky.
- 4Match the color rangeCompare against the expected color range: brown, pink.
- 5Look at form & habitCrystal system: hexagonal. Typical habit: crusts, botryoidal, radiating groups, massive.
Often confused with
Rhabdophane-(La) vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside rhabdophane-(la)
Minerals reported to co-occur with rhabdophane-(la). Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- La(PO₄)·H₂O
- Mohs hardness
- 3-3.5
- Density
- 4.4 g/cm³
- Streak
- White
- Luster
- Greasy to silky
- Transparency
- Semitransparent
- Crystal system
- Hexagonal
- Crystal habit
- Crusts, botryoidal, radiating groups, massive
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- A secondary mineral in faults cutting weathered sediments, probably derived from a porphyritic granite
Where rockhounds find rhabdophane-(la)
Classic worldwide localities
- An undisclosed locality, probably in Kazakhstan
- Mt. Karnasurt, Lovozero massif, Kola Peninsula, Russia
- Silberbrünnle mine, near Gengenbach, Black Forest, Germany
- Gakara, Burundi
Field-hunting tip
Where it forms: A secondary mineral in faults cutting weathered sediments, probably derived from a porphyritic granite. If you start seeing clay minerals, opal in float, you are in the right ground. Typical habit: crusts, botryoidal, radiating groups, massive. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify rhabdophane-(la)?+
Where is rhabdophane-(la) found?+
Is rhabdophane-(la) safe to handle?+
What rocks look like rhabdophane-(la)?+
What minerals are found with rhabdophane-(la)?+
What kind of rock does rhabdophane-(la) form in?+
What is rhabdophane-(la) used for?+
Find rhabdophane-(la) on the map
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