Yecoraite is an extremely rare iron-tellurite mineral known primarily from the Bambollita mine in Sonora, Mexico. It typically occurs as delicate, bright yellow fibrous or radiating needle-like crystals associated with other secondary tellurium minerals in oxidized hydrothermal veins.
Is this yecoraite?
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 yecoraite with a known reference. Yecoraite 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: yellow.
- 3Read the lusterHold the specimen under a strong light. Luster: pitchy.
- 4Match the color rangeCompare against the expected color range: yellow, resin yellow, orange.
- 5Look at form & habitCrystal system: tetragonal. Typical habit: cryptocrystalline.
Often confused with
Yecoraite 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 Yecoraite leaves yellow, Denningite leaves white; luster reads pitchy on Yecoraite and adamantine on Denningite.
How to tell apart: Streak differs, so Yecoraite leaves yellow, Zemannite leaves white; luster reads pitchy on Yecoraite and adamantine on Zemannite.
Often found alongside yecoraite
Minerals reported to co-occur with yecoraite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Fe₃Bi₅O₉(TeO₃)(TeO₄)₂·9H₂O
- Mohs hardness
- 3
- Density
- 5.59 g/cm³
- Streak
- Yellow
- Luster
- Pitchy
- Transparency
- Semitransparent
- Crystal system
- Tetragonal
- Crystal habit
- Cryptocrystalline
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In fractures in a quartz vein emplaced in quartz monzonite, an oxidation product of tetradymite and pyrite
Where rockhounds find yecoraite
Classic worldwide localities
- San Martin de Porres mine, west of Yecora, Sonora, Mexico
Field-hunting tip
Where it forms: In fractures in a quartz vein emplaced in quartz monzonite, an oxidation product of tetradymite and pyrite. If you start seeing tetradymite, pyrite, chalcopyrite in float, you are in the right ground. Typical habit: cryptocrystalline. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify yecoraite?+
Where is yecoraite found?+
What rocks look like yecoraite?+
What minerals are found with yecoraite?+
What kind of rock does yecoraite form in?+
What is yecoraite used for?+
Find yecoraite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
