Varlamoffite is a secondary tin mineral typically occurring as a yellow oxidation product of stannite or cassiterite. It is most commonly found as earthy, powdery masses or thin crusts lining cavities in weathered tin-bearing hydrothermal veins.
Is this varlamoffite?
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 varlamoffite with a known reference. Varlamoffite sits at Mohs 6-6.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: light yellow.
- 3Read the lusterHold the specimen under a strong light. Luster: waxy.
- 4Match the color rangeCompare against the expected color range: yellow, orange red.
- 5Look at form & habitCrystal system: tetragonal. Typical habit: powdery, earthy masses, coatings.
Often confused with
Varlamoffite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Varlamoffite leaves light yellow, Cassiterite leaves white, pale brown, pale gray; luster reads waxy on Varlamoffite and adamantine to adamantine metallic, splendent; may be greasy on fractures on Cassiterite.
How to tell apart: Streak differs, so Varlamoffite leaves light yellow, Limonite leaves yellowish-brown; luster reads waxy on Varlamoffite and submetallic to earthy on Limonite.
Often found alongside varlamoffite
Minerals reported to co-occur with varlamoffite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (Sn,Fe)(O,OH)₂
- Mohs hardness
- 6-6.5
- Density
- 2.52-2.61 g/cm³
- Colors
- Streak
- Light yellow
- Luster
- Waxy
- Transparency
- Translucent
- Crystal system
- Tetragonal
- Crystal habit
- Powdery, earthy masses, coatings
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Oxidized protions of stannite-cassiterite veins
Where rockhounds find varlamoffite
Classic worldwide localities
- Cligga mine, Cronwall, England (type locality)
Field-hunting tip
Where it forms: Oxidized protions of stannite-cassiterite veins. If you start seeing cassiterite, stannite, goethite in float, you are in the right ground. Typical habit: powdery, earthy masses, coatings. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify varlamoffite?+
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What rocks look like varlamoffite?+
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Find varlamoffite on the map
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