Dagenaisite is a very rare zinc tellurite mineral discovered in the oxidized zones of tellurium-rich ore deposits. It typically forms small, greenish gray tabular crystals that are often identified through micro-analysis due to its scarcity.
Is this dagenaisite?
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 dagenaisite with a known reference. Dagenaisite sits at Mohs ~2, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: white.
- 3Read the lusterHold the specimen under a strong light. Luster: pearly.
- 4Match the color rangeCompare against the expected color range: greenish gray.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: tabular crystals.
Often confused with
Dagenaisite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Zincite is the harder of the two (Mohs 4 vs. ~2); streak differs, so Dagenaisite leaves white, Zincite leaves yellow-orange; luster reads pearly on Dagenaisite and subadamantine to resinous on Zincite.
How to tell apart: Streak differs, so Dagenaisite leaves white, Teineite leaves pale blue; luster reads pearly on Dagenaisite and vitreous on Teineite.
Often found alongside dagenaisite
Minerals reported to co-occur with dagenaisite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Zn₃TeO₆
- Mohs hardness
- ~2
- Density
- 6.00 g/cm³
- Colors
- Streak
- White
- Luster
- Pearly
- Transparency
- Transparent to translucent
- Crystal system
- Monoclinic
- Crystal habit
- Tabular crystals
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- A late-stage secondary phase formed by the oxidative alteration of earlier Te- and Zn-bearing minerals, probably hessite and sphalerite in a polymetallic vein deposit
Where rockhounds find dagenaisite
Classic worldwide localities
- Moctezuma mine, Sonora, Mexico
Field-hunting tip
Where it forms: A late-stage secondary phase formed by the oxidative alteration of earlier Te- and Zn-bearing minerals, probably hessite and sphalerite in a polymetallic vein deposit. If you start seeing cinnabar, dugganite, eurekadumpite in float, you are in the right ground. Typical habit: tabular crystals. Train your eye for that shape before scanning the outcrop.
Common questions
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Find dagenaisite on the map
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