Aspedamite is a rare, radioactive member of the allanite group that typically presents as massive, dark-colored grains within pegmatites. It is primarily found at its type locality in Aspedam, Norway, and is valued by specialist collectors of radioactive and rare-earth minerals.
Is this aspedamite?
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 aspedamite with a known reference. Aspedamite sits at Mohs 5.5-6, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Aspedamite leaves a brownish streak.
- 3Read the lusterHold the specimen under a strong light. Aspedamite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: brown, black.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: massive.
Often confused with
Aspedamite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Aspedamite leaves brownish, Allanite leaves gray; luster reads vitreous on Aspedamite and submetallic on Allanite.
How to tell apart: Streak differs, so Aspedamite leaves brownish, Epidote leaves white.
Often found alongside aspedamite
Minerals reported to co-occur with aspedamite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- CaREEFe³⁺AlFe²⁺Si₃O₁₂(OH)
- Mohs hardness
- 5.5-6
- Density
- 4.2-4.3 g/cm³
- Streak
- Brownish
- Luster
- Vitreous
- Transparency
- Opaque
- Crystal system
- Monoclinic
- Crystal habit
- Massive
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Pegmatites
- Typical price
- $20-100 per specimen
Where rockhounds find aspedamite
Classic worldwide localities
- Aspedam, Østfold, Norway
Field-hunting tip
Look in pegmatites country, the host setting where aspedamite typically forms. If you start seeing microcline, quartz, biotite in float, you are in the right ground. Field specimens usually show a massive habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify aspedamite?+
Where is aspedamite found?+
How much is aspedamite worth?+
Is aspedamite safe to handle?+
What rocks look like aspedamite?+
What minerals are found with aspedamite?+
What kind of rock does aspedamite form in?+
What is aspedamite used for?+
Find aspedamite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
