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, so Tamboite leaves yellow, Pharmacosiderite leaves white; luster reads resinous on Tamboite and adamantine on Pharmacosiderite.
How to tell apart: Streak differs, so 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, 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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