Alumoedtollite is a rare potassium sodium copper arsenate. It is a sublimate on basaltic scoria at an active volcanic fumarole. It was first described from the Arsenatnaya fumarole, Tolbachik Volcano, Kamchatka, Russia.
Is this alumoedtollite?
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 alumoedtollite with a known reference. Alumoedtollite sits at Mohs 2-3, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: light yellow.
- 3Read the lusterHold the specimen under a strong light. Luster: semi-metallic.
- 4Match the color rangeCompare against the expected color range: bronze.
- 5Look at form & habitCrystal system: triclinic. Typical habit: tabular crystals.
Often confused with
Alumoedtollite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Natrolite is the harder of the two (Mohs 5-5.5 vs. 2-3); streak differs, so Alumoedtollite leaves light yellow, Natrolite leaves white; luster reads semi-metallic on Alumoedtollite and vitreous to pearly on Natrolite.
How to tell apart: Gonnardite is the harder of the two (Mohs 5 vs. 2-3); streak differs, so Alumoedtollite leaves light yellow, Gonnardite leaves white; luster reads semi-metallic on Alumoedtollite and silky on Gonnardite.
Often found alongside alumoedtollite
Minerals reported to co-occur with alumoedtollite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- K₂NaCu₅AlO₂(AsO₄)₄
- Mohs hardness
- 2-3
- Density
- 4.280 g/cm³
- Colors
- Streak
- Light yellow
- Luster
- Semi-metallic
- Transparency
- Translucent to almost opaque
- Crystal system
- Triclinic
- Crystal habit
- Tabular crystals
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- A sublimate on basaltic scoria at an active volcanic fumarole
Where rockhounds find alumoedtollite
Classic worldwide localities
- Arsenatnaya fumarole, Second scoria cone, Northern Breakthrough of the Great Tolbachik Fissure Eruption, Tolbachik Volcano, Kamchatka, Russia
Field-hunting tip
Where it forms: A sublimate on basaltic scoria at an active volcanic fumarole. If you start seeing sylvite, halite, tenorite in float, you are in the right ground. Typical habit: tabular crystals. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify alumoedtollite?+
Where is alumoedtollite found?+
Is alumoedtollite safe to handle?+
What rocks look like alumoedtollite?+
What minerals are found with alumoedtollite?+
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Find alumoedtollite on the map
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