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 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Spiroffite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Spiroffite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: colorless, white, pale yellow.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: tabular to prismatic crystals.
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 vs. 2); luster reads vitreous on Spiroffite and adamantine on Tellurite.
How to tell apart: Spiroffite is noticeably harder (Mohs 3 vs. 2); luster reads vitreous on Spiroffite and adamantine 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
- (Zn,Mn)₂Te₃O₈
- Mohs hardness
- 3
- Density
- 6.0-6.1 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Tabular to Prismatic Crystals
- Cleavage
- Good On {010}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Oxidized Tellurium-bearing Hydrothermal Deposits
- Typical price
- $50-300 per specimen depending on size and crystal quality
Where rockhounds find spiroffite
Classic worldwide localities
- Tombstone, Arizona (USA)
- Moctezuma, Sonora (Mexico)
Field-hunting tip
Look in oxidized tellurium-bearing hydrothermal deposits country — that is the host setting where spiroffite typically forms. If you start seeing tellurite, paratellurite, emmonsite in float, you are in the right ground. Field specimens usually show a tabular to prismatic crystals habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find spiroffite on the map
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