Tveitite-(Y) is a rare yttrium-calcium fluoride mineral found primarily in granitic pegmatites. It is highly prized by collectors for its distinctive bright white fluorescence under short-wave ultraviolet light, which helps differentiate it from common fluorite.
Is this tveitite-(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 tveitite-(y) with a known reference. Tveitite-(Y) sits at Mohs 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.
- 4Match the color rangeCompare against the expected color range: white, light yellow.
- 5Look at form & habitCrystal system: trigonal. Typical habit: rhombohedral crystals, massive.
Often confused with
Tveitite-(Y) vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside tveitite-(y)
Minerals reported to co-occur with tveitite-(y). Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (Y,Na)₆(Ca,Na,Y,REE)₁₂(Ca,Na)F₄₂
- Mohs hardness
- 3.5
- Density
- 3.94 g/cm³
- Colors
- Streak
- White
- Luster
- Greasy
- Transparency
- Transparent
- Crystal system
- Trigonal
- Crystal habit
- Rhombohedral crystals, massive
- Cleavage
- None
- Fluorescence
- Faint yellow orange under SW UV
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In a pegmatite dike in amphibolites, probably formed by inversion of yttrofluorite
Where rockhounds find tveitite-(y)
Classic worldwide localities
- Høydalen, Tørdal, Telemark, Norway
Field-hunting tip
Where it forms: In a pegmatite dike in amphibolites, probably formed by inversion of yttrofluorite. If you start seeing kainosite, fluocerite, cerianite in float, you are in the right ground. Typical habit: rhombohedral crystals, massive. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify tveitite-(y)?+
Where is tveitite-(y) found?+
What rocks look like tveitite-(y)?+
What minerals are found with tveitite-(y)?+
What kind of rock does tveitite-(y) form in?+
What is tveitite-(y) used for?+
Find tveitite-(y) on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
