Spiroffite is a very rare zinc tellurite mineral typically found in oxidized zones of tellurium-rich ore deposits. Collectors should look for small, transparent tabular crystals often associated with other tellurium minerals in specimens from the Tombstone or Moctezuma districts.
Is this spiroffite?
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 spiroffite with a known reference. Spiroffite sits at Mohs ~3.5, 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: adamantine.
- 4Match the color rangeCompare against the expected color range: red, purple.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: comb, massive.
Often confused with
Spiroffite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Spiroffite is noticeably harder (Mohs ~3.5 vs. 2); luster reads adamantine on Spiroffite and subadamantine on Tellurite.
How to tell apart: Spiroffite is noticeably harder (Mohs ~3.5 vs. 1); luster reads adamantine on Spiroffite and resinous to waxy on Paratellurite.
Often found alongside spiroffite
Minerals reported to co-occur with spiroffite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Mn₂Te₃O₈
- Mohs hardness
- ~3.5
- Density
- 5.01 g/cm³
- Streak
- White
- Luster
- Adamantine
- Transparency
- Transparent to translucent
- Crystal system
- Monoclinic
- Crystal habit
- Comb, massive
- Cleavage
- Observed in at least two directions
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Very rare in the oxidized zone of an Au–Te deposit (Moctezuma mine, Mexico); very rare in intensely silicified pyritic shales (Joe mine, Arizona, USA)
Where rockhounds find spiroffite
Classic worldwide localities
- Joe mine, Tombstone, Cochise Co., Arizona, USA
- Moctezuma (Bambolla) mine, 12 km south of Moctezuma, Sonora, Mexico
- Kawazu mine, Shizuoka Prefecture, Japan
Field-hunting tip
Where it forms: Very rare in the oxidized zone of an Au–Te deposit (Moctezuma mine, Mexico); very rare in intensely silicified pyritic shales (Joe mine, Arizona, USA). If you start seeing tellurium, tellurite, paratellurite in float, you are in the right ground. Typical habit: comb, massive. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify spiroffite?+
Where is spiroffite found?+
Is spiroffite safe to handle?+
What rocks look like spiroffite?+
What minerals are found with spiroffite?+
What kind of rock does spiroffite form in?+
What is spiroffite used for?+
Find spiroffite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
