Angelellite is a rare iron arsenate mineral primarily found in specific hydrothermal deposits in Argentina. Collectors should look for its distinctive tabular red-to-brown crystals often associated with hematite or bixbyite.
Is this angelellite?
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 angelellite with a known reference. Angelellite sits at Mohs 5.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: reddish brown.
- 3Read the lusterHold the specimen under a strong light. Luster: adamantine to semimetallic.
- 4Match the color rangeCompare against the expected color range: black brown.
- 5Look at form & habitCrystal system: triclinic. Typical habit: tabular crystals.
Often confused with
Angelellite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Angelellite leaves reddish brown, Hematite leaves cherry-red or reddish brown; luster reads adamantine to semimetallic on Angelellite and metallic or submetallic to dull on Hematite.
How to tell apart: Streak differs, so Angelellite leaves reddish brown, Goethite leaves brownish yellow, yellow-orange, ocher-yellow; luster reads adamantine to semimetallic on Angelellite and imperfect adamantine metallic to dull earthy; silky when fibrous on Goethite.
Often found alongside angelellite
Minerals reported to co-occur with angelellite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Fe₄(AsO₄)₂O₃
- Mohs hardness
- 5.5
- Density
- 4.867 g/cm³
- Colors
- Streak
- Reddish brown
- Luster
- Adamantine to semimetallic
- Transparency
- Semitransparent
- Crystal system
- Triclinic
- Crystal habit
- Tabular crystals
- Cleavage
- On {001}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Probably of exhalative origin, in tin ore
Where rockhounds find angelellite
Classic worldwide localities
- Vela Yareta tin mine, on Cerro Pululus, east of Laguna Vilama, Jujuy Province, Argentina
Field-hunting tip
Where it forms: Probably of exhalative origin, in tin ore. If you start seeing cassiterite, hematite 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 angelellite?+
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Is angelellite safe to handle?+
What rocks look like angelellite?+
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Find angelellite on the map
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