Thermaerogenite is a rare copper-aluminum oxide belonging to the spinel group, typically formed in volcanic fumarole environments. It usually appears as small, dark octahedral crystals deposited from volcanic gases.
Is this thermaerogenite?
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 thermaerogenite with a known reference. Thermaerogenite sits at Mohs 7.5-8, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Thermaerogenite leaves a yellow streak.
- 3Read the lusterHold the specimen under a strong light. Thermaerogenite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: brown, yellow-brown, red-brown, brown- yellow.
- 5Look at form & habitCrystal system: cubic. Typical habit: octahedral.
Often confused with
Thermaerogenite vs. its common look-alikes, and how to tell them apart in the field.
All properties
- Chemical formula
- CuAl₂O₄
- Mohs hardness
- 7.5-8
- Density
- 4.45 g/cm³
- Streak
- Yellow
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Cubic
- Crystal habit
- Octahedral
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Fumarolic Encrustations
Where rockhounds find thermaerogenite
Classic worldwide localities
- Vesuvius (Italy)
Field-hunting tip
Look in fumarolic encrustations country, the host setting where thermaerogenite typically forms. If you start seeing copper minerals, aluminosilicates in float, you are in the right ground. Field specimens usually show a octahedral habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify thermaerogenite?+
Where is thermaerogenite found?+
What rocks look like thermaerogenite?+
What minerals are found with thermaerogenite?+
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What is thermaerogenite used for?+
Find thermaerogenite on the map
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