Theoparacelsite is a rare copper arsenic hydroxide, typically dark pistachio-green. It is a secondary mineral within ~1 mm geodes of cuprite. It was first described from the old Cu mines of Roua, western margin of the Barrot Dome, Alpes-Maritimes, France.
Is this theoparacelsite?
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 theoparacelsite with a known reference. Theoparacelsite sits at Mohs 3.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: yellowish green.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous to adamantine.
- 4Match the color rangeCompare against the expected color range: dark pistachio green.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: anhedral grains, pseudomorphous, pulverulent.
Often confused with
Theoparacelsite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Theoparacelsite leaves yellowish green, Volborthite leaves light green.
How to tell apart: Streak differs, so Theoparacelsite leaves yellowish green, Malachite leaves pale green; luster reads vitreous to adamantine on Theoparacelsite and adamantine to vitreous; silky if fibrous; dull to earthy if massive on Malachite.
Often found alongside theoparacelsite
Minerals reported to co-occur with theoparacelsite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Cu₃(OH)₂As₂O₇(OH)₂
- Mohs hardness
- 3.5
- Density
- 4.72 g/cm³
- Colors
- Dark pistachio green
- Streak
- Yellowish green
- Luster
- Vitreous to adamantine
- Transparency
- Translucent
- Crystal system
- Orthorhombic
- Crystal habit
- Anhedral grains, pseudomorphous, pulverulent
- Cleavage
- Perfect on {001}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- A secondary mineral within ~1 mm geodes of cuprite
Where rockhounds find theoparacelsite
Classic worldwide localities
- Old Cu mines of Roua, Alpes-Maritimes, France
Field-hunting tip
Where it forms: A secondary mineral within ~1 mm geodes of cuprite. If you start seeing olivenite, cornubite, connellite in float, you are in the right ground. Typical habit: anhedral grains, pseudomorphous, pulverulent. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify theoparacelsite?+
Where is theoparacelsite found?+
Is theoparacelsite safe to handle?+
What rocks look like theoparacelsite?+
What minerals are found with theoparacelsite?+
What kind of rock does theoparacelsite form in?+
What is theoparacelsite used for?+
Find theoparacelsite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
