Samarskite-(Y) is a complex radioactive oxide mineral typically found in granite pegmatites. It is often identified by its dark, shiny appearance, submetallic luster, and tendency to form blocky or prismatic crystals that are frequently metamict due to internal radiation damage.
Is this samarskite-(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 samarskite-(y) with a known reference. Samarskite-(Y) 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: dark reddish brown to black, yellow-brown; gray when altered.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous to resinous, may be submetallic, splendent; externally dull.
- 4Match the color rangeCompare against the expected color range: black, brownish, yellowish brown.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: massive.
Often confused with
Samarskite-(Y) vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Samarskite-(Y) leaves dark reddish brown to black, yellow-brown; gray when altered, Columbite leaves blackish brown; luster reads vitreous to resinous, may be submetallic, splendent; externally dull on Samarskite-(Y) and submetallic on Columbite.
How to tell apart: Streak differs, so Samarskite-(Y) leaves dark reddish brown to black, yellow-brown; gray when altered, Euxenite-(Y) leaves yellowish, grayish, or reddish brown; luster reads vitreous to resinous, may be submetallic, splendent; externally dull on Samarskite-(Y) and brilliant submetallic, waxy to resinous on fractures on Euxenite-(Y).
Often found alongside samarskite-(y)
Minerals reported to co-occur with samarskite-(y). Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- YFe³⁺Nb₂O₈
- Mohs hardness
- 5-6
- Density
- 5.0-5.69 g/cm³
- Streak
- Dark reddish brown to black, yellow-brown; gray when altered
- Luster
- Vitreous to resinous, may be submetallic, splendent; externally dull
- Transparency
- Opaque, transparent in thin fragments
- Crystal system
- Orthorhombic
- Crystal habit
- Massive
- Cleavage
- {010}, indistinct
- Rarity
- Rare
- Uses
- Collector, Ore of rare earth elements
- Host rock
- An accessory mineral in RE-rich granite pegmatites, common but not abundant; rarely as a detrital mineral
Where rockhounds find samarskite-(y)
Classic worldwide localities
- Glastonbury, Hartford Co., Connecticut, USA
- Mitchell pegmatite, Bedford Co., Virginia, USA
- Spruce Pine, Mitchell Co., North Carolina, USA
- Nuevo, Riverside Co., California, USA
- Miass, Ilmen Mountains, Southern Ural Mountains, Russia
- Ånneröd, Iveland, and Setesdal districts, Norway
Field-hunting tip
Where it forms: An accessory mineral in RE-rich granite pegmatites, common but not abundant; rarely as a detrital mineral. If you start seeing columbite, zircon, monazite in float, you are in the right ground. Typical habit: massive. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify samarskite-(y)?+
Where is samarskite-(y) found?+
Is samarskite-(y) safe to handle?+
What rocks look like samarskite-(y)?+
What minerals are found with samarskite-(y)?+
What kind of rock does samarskite-(y) form in?+
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Find samarskite-(y) on the map
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