Bastnäsite-(Y) is a rare rare-earth carbonate mineral typically found in complex alkaline environments. It is often distinguished from the more common Cerium-dominant variety by its Yttrium content and specific paragenesis, often appearing as small, sharp tabular crystals in pegmatite pockets.
Is this bastnäsite-(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 bastnäsite-(y) with a known reference. Bastnäsite-(Y) sits at Mohs 4-4.5, 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: vitreous to greasy.
- 4Match the color rangeCompare against the expected color range: yellow, reddish brown.
- 5Look at form & habitCrystal system: hexagonal. Typical habit: massive, prismatic.
Often confused with
Bastnäsite-(Y) vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside bastnäsite-(y)
Minerals reported to co-occur with bastnäsite-(y). Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Y(CO₃)F
- Mohs hardness
- 4-4.5
- Density
- 3.9-4.0 g/cm³
- Colors
- Streak
- White
- Luster
- Vitreous to greasy
- Transparency
- Translucent
- Crystal system
- Hexagonal
- Crystal habit
- Massive, prismatic
- Cleavage
- Imperfect on {1011}; indistinct on {0001}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- A rare secondary mineral in a microcline–quartz pegmatite vein
Where rockhounds find bastnäsite-(y)
Classic worldwide localities
- Verkhne-Espe alkaline massif, Tarbagatai Range, Kazakhstan
Field-hunting tip
Where it forms: A rare secondary mineral in a microcline–quartz pegmatite vein. If you start seeing gagarinite-, fluorite, microcline 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 bastnäsite-(y)?+
Where is bastnäsite-(y) found?+
Is bastnäsite-(y) safe to handle?+
What rocks look like bastnäsite-(y)?+
What minerals are found with bastnäsite-(y)?+
What kind of rock does bastnäsite-(y) form in?+
What is bastnäsite-(y) used for?+
Find bastnäsite-(y) on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
