Tlapallite is a rare secondary tellurium mineral typically found as small, vibrant yellow to greenish-yellow crusts or powdery coatings. It is primarily associated with oxidized telluride ore deposits, where it forms in the transition zones of weathered mineral veins.
Is this tlapallite?
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 tlapallite with a known reference. Tlapallite sits at Mohs 3, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: pale green.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: green, cyprus green.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: encrustations, thin.
Often confused with
Tlapallite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Denningite is the harder of the two (Mohs 4 vs. 3); streak differs, so Tlapallite leaves pale green, Denningite leaves white; luster reads vitreous on Tlapallite and adamantine on Denningite.
How to tell apart: Streak differs, so Tlapallite leaves pale green, Zemannite leaves white; luster reads vitreous on Tlapallite and adamantine on Zemannite.
Often found alongside tlapallite
Minerals reported to co-occur with tlapallite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (Ca,Pb)₃CaCu₆[Te₃TeO₁₂]₂(TeO₃)₂(SO₄)₂·3H₂O
- Mohs hardness
- 3
- Density
- 5.38 g/cm³
- Colors
- GreenCyprus green
- Streak
- Pale green
- Luster
- Vitreous
- Transparency
- Semitransparent
- Crystal system
- Monoclinic
- Crystal habit
- Encrustations, thin
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Very rare in partially oxidized portions of a tellurium-bearing polymetallic hydrothermal sulfide deposit (Moctezuma mine, Mexico); an alteration product of tellurides in calcsilicate tactite (Tombstone, Arizona)
Where rockhounds find tlapallite
Classic worldwide localities
- Tombstone, Cochise Co., Arizona, from the Lucky Cuss and Emerald mines, USA
- Moctezuma (Bambolla) mine, 12 km south of Moctezuma, Sonora, Mexico
Field-hunting tip
Where it forms: Very rare in partially oxidized portions of a tellurium-bearing polymetallic hydrothermal sulfide deposit (Moctezuma mine, Mexico); an alteration product of tellurides in calcsilicate tactite (Tombstone, Arizona). If you start seeing carlfriesite, calcite, barite in float, you are in the right ground. Typical habit: encrustations, thin. Train your eye for that shape before scanning the outcrop.
Common questions
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Find tlapallite on the map
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