Friedrichbeckeite is a very rare beryllium-rich silicate mineral belonging to the milarite group. It typically occurs as small, transparent hexagonal prisms in granitic pegmatites and is primarily sought after by advanced mineral collectors due to its extreme rarity and limited locality occurrences.
Is this friedrichbeckeite?
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 friedrichbeckeite with a known reference. Friedrichbeckeite sits at Mohs 6, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: colorless to pale cream.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: light yellow.
- 5Look at form & habitCrystal system: hexagonal. Typical habit: tabular.
Often confused with
Friedrichbeckeite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Friedrichbeckeite leaves colorless to pale cream, Milarite leaves white.
How to tell apart: Beryl is the harder of the two (Mohs 7.5-8 vs. 6); streak differs, so Friedrichbeckeite leaves colorless to pale cream, Beryl leaves white.
Often found alongside friedrichbeckeite
Minerals reported to co-occur with friedrichbeckeite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- K(□Na)Mg₂(MgBe₂Si₁₂)O₃₀
- Mohs hardness
- 6
- Density
- 2.686 g/cm³
- Colors
- Streak
- Colorless to pale cream
- Luster
- Vitreous
- Transparency
- Transparent to translucent
- Crystal system
- Hexagonal
- Crystal habit
- Tabular
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In vesicles in pyrometamorphically metasomatized silicate-rich xenoliths in leucite-tephrite volcanic rock
Where rockhounds find friedrichbeckeite
Classic worldwide localities
- Bellerberg volcano, southeast of Ettringen, East Eifel volcanic area, Germany
Field-hunting tip
Where it forms: In vesicles in pyrometamorphically metasomatized silicate-rich xenoliths in leucite-tephrite volcanic rock. If you start seeing tridymite, augite, magnesiohornblende in float, you are in the right ground. Typical habit: tabular. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify friedrichbeckeite?+
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Is friedrichbeckeite safe to handle?+
What rocks look like friedrichbeckeite?+
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Find friedrichbeckeite on the map
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