Tvedalite is a rare beryllium-bearing silicate mineral typically found as delicate, radiating spherical aggregates. It is most famous for its discovery in the alkaline igneous rocks of the Tvedalen area in Norway, often appearing as coatings or small balls in pegmatite cavities. Collectors prize it for its unique habit and rarity in mineral suites.
Is this tvedalite?
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 tvedalite with a known reference. Tvedalite sits at Mohs 3-4 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Tvedalite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Tvedalite typically shows a pearly luster.
- 4Match the color rangeCompare against the expected color range: white, yellowish-white, pale yellow.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: spherulitic aggregates, radial clusters.
Often confused with
Tvedalite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside tvedalite
Minerals reported to co-occur with tvedalite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (Ca,Mn)₄Be₃Si₆O₁₇(OH)₂·6H₂O
- Mohs hardness
- 3-4
- Density
- 2.16 g/cm³
- Streak
- White
- Luster
- Pearly
- Transparency
- Translucent
- Crystal system
- Orthorhombic
- Crystal habit
- Spherulitic Aggregates, Radial Clusters
- Cleavage
- Perfect
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Nepheline Syenite Pegmatites
- Typical price
- $50-300 per specimen
Where rockhounds find tvedalite
Classic worldwide localities
- Tvedalen, Larvik, Norway
- Varennes quarry, Quebec, Canada
Field-hunting tip
Look in nepheline syenite pegmatites country — that is the host setting where tvedalite typically forms. If you start seeing leucophanite, fluorite, quartz in float, you are in the right ground. Field specimens usually show a spherulitic aggregates, radial clusters habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify tvedalite?+
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How much is tvedalite worth?+
What rocks look like tvedalite?+
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Find tvedalite on the map
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