Tamboite is a very rare secondary arsenic-bearing sulfate mineral found primarily in oxidized hydrothermal deposits. It is typically identified by its distinct yellow color and needle-like acicular crystal clusters found within vugs of oxidized sulfide ore.
Is this tamboite?
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 tamboite with a known reference. Tamboite 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: very pale yellow to colorless.
- 3Read the lusterHold the specimen under a strong light. Luster: greasy to vitreous.
- 4Match the color rangeCompare against the expected color range: pale yellow.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: acicular crystals, radiating clusters.
Often confused with
Tamboite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Tamboite leaves very pale yellow to colorless, Pharmacosiderite leaves yellowish green; luster reads greasy to vitreous on Tamboite and adamantine to greasy on Pharmacosiderite.
How to tell apart: Streak differs, so Tamboite leaves very pale yellow to colorless, Scorodite leaves greenish white; luster reads greasy to vitreous on Tamboite and vitreous to subadamantine, subresinous on Scorodite.
Often found alongside tamboite
Minerals reported to co-occur with tamboite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Fe₃(OH)(H₂O)₂(SO₄)(TeO₃)₃(TeO(OH)₂)(H₂O)₃
- Mohs hardness
- 2-3
- Density
- 3.648 g/cm³
- Colors
- Streak
- Very pale yellow to colorless
- Luster
- Greasy to vitreous
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Acicular crystals, radiating clusters
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In the interstices of silicified epithermal hydrothermal breccias of dacitic tuff
Where rockhounds find tamboite
Classic worldwide localities
- Tambo Mine, Argentina
Field-hunting tip
Where it forms: In the interstices of silicified epithermal hydrothermal breccias of dacitic tuff. If you start seeing alunite, rodalquilarite, emmonsite in float, you are in the right ground. Typical habit: acicular crystals, radiating clusters. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify tamboite?+
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Find tamboite on the map
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