Graulichite-(Ce) is a very rare member of the beudantite group occurring as tiny yellow to brownish-yellow crystals. It is primarily found as a secondary mineral in oxidized zones of arsenate-rich ore deposits, typically requiring magnification to identify crystal form.
Is this graulichite-(ce)?
4-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 graulichite-(ce) with a known reference. Graulichite-(Ce) sits at Mohs 4, softer than the next harder reference, harder than the previous one.
- 2Read the lusterHold the specimen under a strong light. Luster: resinous.
- 3Match the color rangeCompare against the expected color range: light green, brownish green.
- 4Look at form & habitCrystal system: trigonal. Typical habit: aggregates, rhombohedral crystals, spherical.
Often confused with
Graulichite-(Ce) vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Luster reads resinous on Graulichite-(Ce) and vitreous, resinous, may be frosted on Beudantite.
How to tell apart: Luster reads resinous on Graulichite-(Ce) and vitreous to resinous on Corkite.
How to tell apart: Luster reads resinous on Graulichite-(Ce) and vitreous to adamantine on Segnitite.
Often found alongside graulichite-(ce)
Minerals reported to co-occur with graulichite-(ce). Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- CeFe³⁺₃(AsO₄)₂(OH)₆
- Mohs hardness
- 4
- Density
- 3.9 g/cm³
- Luster
- Resinous
- Transparency
- Transparent
- Crystal system
- Trigonal
- Crystal habit
- Aggregates, rhombohedral crystals, spherical
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- A secondary mineral formed by weathering of arsenopyrite-bearing metaquartzite
Where rockhounds find graulichite-(ce)
Classic worldwide localities
- Hourt quarry, 2 km north of Vielsalm, Stavelot massif, Belgian Ardennes
Field-hunting tip
Where it forms: A secondary mineral formed by weathering of arsenopyrite-bearing metaquartzite. If you start seeing scorodite, mimetite, goethite in float, you are in the right ground. Typical habit: aggregates, rhombohedral crystals, spherical. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify graulichite-(ce)?+
Where is graulichite-(ce) found?+
Is graulichite-(ce) safe to handle?+
What rocks look like graulichite-(ce)?+
What minerals are found with graulichite-(ce)?+
What kind of rock does graulichite-(ce) form in?+
What is graulichite-(ce) used for?+
Find graulichite-(ce) on the map
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