Werdingite is a rare borosilicate mineral found primarily in high-grade metamorphic environments. It typically occurs as small, brownish prismatic crystals or granular masses embedded within granulite or khondalite rocks.
Is this werdingite?
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 werdingite with a known reference. Werdingite sits at Mohs 7, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: buff-white.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: brownish yellow.
- 5Look at form & habitCrystal system: triclinic. Typical habit: anhedral grains.
Often confused with
Werdingite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Werdingite leaves buff-white, Sillimanite leaves white.
How to tell apart: Streak differs, so Werdingite leaves buff-white, Andalusite leaves white.
How to tell apart: Streak differs, so Werdingite leaves buff-white, Kyanite leaves white.
Often found alongside werdingite
Minerals reported to co-occur with werdingite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Mg₂Al₁₄Si₄B₄O₃₇
- Mohs hardness
- 7
- Density
- 3.04 g/cm³
- Colors
- Streak
- Buff-white
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Triclinic
- Crystal habit
- Anhedral grains
- Cleavage
- Prismatic, poor, or a parting
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In granulite facies metamorphosed metasediments and metavolcanic cordierite-sillimanite and biotite gneisses
Where rockhounds find werdingite
Classic worldwide localities
- Bok se Puts Farm, Namaqualand, Cape Province, South Africa
Field-hunting tip
Where it forms: In granulite facies metamorphosed metasediments and metavolcanic cordierite-sillimanite and biotite gneisses. If you start seeing kornerupine, grandidierite, sillimanite in float, you are in the right ground. Typical habit: anhedral grains. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify werdingite?+
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What rocks look like werdingite?+
What minerals are found with werdingite?+
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Find werdingite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
