Thalénite-(Y) is a rare yttrium silicate mineral that typically forms in granite pegmatites. Collectors generally look for its distinctive pink or flesh-red tabular crystals often associated with other rare earth minerals.
Is this thalénite-(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 thalénite-(y) with a known reference. Thalénite-(Y) sits at Mohs 6-6.5, 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.
- 4Match the color rangeCompare against the expected color range: pink, brownish green, brown.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: prismatic, tabular.
Often confused with
Thalénite-(Y) vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside thalénite-(y)
Minerals reported to co-occur with thalénite-(y). Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Y₃Si₃O₁₀F
- Mohs hardness
- 6-6.5
- Density
- 4.16-4.41 g/cm³
- Colors
- Streak
- White
- Luster
- Greasy
- Transparency
- Transparent to opaque
- Crystal system
- Monoclinic
- Crystal habit
- Prismatic, tabular
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In granite pegmatites
Where rockhounds find thalénite-(y)
Classic worldwide localities
- Baringer Hill pegmatite, 26 km west of Burnet, Llano Co., Texas, USA
- Snowflake feldspar mine, Teller Co., and the White Cloud pegmatite, South Platte district, Jefferson Co., Colorado, USA
- Guy Hazen claims, seven km south of Kingman, Mohave Co., Arizona, USA
- Hundholmen, Tysfjord, and Kragerö, Nordland, Norway
- Högetveit, Evje, Norway
- Rossås, Setesdal, Norway
Field-hunting tip
Where it forms: In granite pegmatites. If you start seeing fluocerite, fergusonite, gadolinite in float, you are in the right ground. Typical habit: prismatic, tabular. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify thalénite-(y)?+
Where is thalénite-(y) found?+
Is thalénite-(y) safe to handle?+
What rocks look like thalénite-(y)?+
What minerals are found with thalénite-(y)?+
What kind of rock does thalénite-(y) form in?+
What is thalénite-(y) used for?+
Find thalénite-(y) on the map
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