Samarskite-(Yb) is a rare radioactive yttrium-niobium mineral typically found in complex granite pegmatites. It is often metamict due to internal radiation damage, meaning its internal crystal structure has been destroyed over time, resulting in a glass-like appearance.
Is this samarskite-(yb)?
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 samarskite-(yb) with a known reference. Samarskite-(Yb) sits at Mohs 5-6, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: brown black.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: black.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: metamict.
Often confused with
Samarskite-(Yb) vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Samarskite-(Yb) leaves brown black, Columbite leaves blackish brown; luster reads vitreous on Samarskite-(Yb) and submetallic on Columbite.
How to tell apart: Streak differs, so Samarskite-(Yb) leaves brown black, Tantalite leaves black to reddish-brown; luster reads vitreous on Samarskite-(Yb) and submetallic to resinous on Tantalite.
How to tell apart: Streak differs, so Samarskite-(Yb) leaves brown black, Euxenite-(Y) leaves yellowish, grayish, or reddish brown; luster reads vitreous on Samarskite-(Yb) and brilliant submetallic, waxy to resinous on fractures on Euxenite-(Y).
Often found alongside samarskite-(yb)
Minerals reported to co-occur with samarskite-(yb). Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- YbNbO₄
- Mohs hardness
- 5-6
- Density
- 7.03 g/cm³
- Colors
- Streak
- Brown black
- Luster
- Vitreous
- Transparency
- Opaque
- Crystal system
- Monoclinic
- Crystal habit
- Metamict
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Found as anhedral masses up to tens of centimeters across that are intimately intergrown with ferrocolumbite and zircon
Where rockhounds find samarskite-(yb)
Classic worldwide localities
- Little Patsy pegmatite, Jefferson Co., Colorado, USA (type locality)
Field-hunting tip
Where it forms: Found as anhedral masses up to tens of centimeters across that are intimately intergrown with ferrocolumbite and zircon. If you start seeing zircon, monazite, beryl in float, you are in the right ground. Typical habit: metamict. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify samarskite-(yb)?+
Where is samarskite-(yb) found?+
Is samarskite-(yb) safe to handle?+
What rocks look like samarskite-(yb)?+
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Find samarskite-(yb) on the map
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