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. Tamboite leaves a yellow streak.
- 3Read the lusterHold the specimen under a strong light. Tamboite typically shows a resinous luster.
- 4Match the color rangeCompare against the expected color range: yellow, yellowish-orange.
- 5Look at form & habitCrystal system: orthorhombic. 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 — Tamboite leaves yellow, Pharmacosiderite leaves white; luster reads resinous on Tamboite and adamantine on Pharmacosiderite.
How to tell apart: Streak differs — Tamboite leaves yellow, Scorodite leaves white; luster reads resinous on Tamboite and vitreous to sub-adamantine 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
- Fe₂₄(AsO₃)₁₆(SO₄)₅O₁₂(OH)₂·33H₂O
- Mohs hardness
- 2-3
- Density
- 2.86 g/cm³
- Colors
- Streak
- Yellow
- Luster
- Resinous
- Transparency
- Translucent
- Crystal system
- Orthorhombic
- Crystal habit
- Acicular Crystals, Radiating Clusters
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Hydrothermal Veins
- Typical price
- $50-300 per specimen
Where rockhounds find tamboite
Classic worldwide localities
- Tambo Mine, Argentina
Field-hunting tip
Look in hydrothermal veins country — that is the host setting where tamboite typically forms. If you start seeing arsenopyrite, pyrite, jarosite in float, you are in the right ground. Field specimens usually show a acicular crystals, radiating clusters habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find tamboite on the map
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