Sorosite is an extremely rare copper-tin alloy mineral found primarily as tiny grains in alluvial deposits. It is identifiable by its bright metallic luster and silver-white appearance, often requiring analytical testing for positive identification due to its similarity to other tin-bearing minerals.
Is this sorosite?
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 sorosite with a known reference. Sorosite sits at Mohs 3.5-4, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Sorosite leaves a silver-white streak.
- 3Read the lusterHold the specimen under a strong light. Sorosite typically shows a metallic luster.
- 4Match the color rangeCompare against the expected color range: silver-white, tin-white.
- 5Look at form & habitCrystal system: hexagonal. Typical habit: massive, anhedral grains.
Often confused with
Sorosite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Sorosite leaves silver-white, Stannite leaves black.
How to tell apart: Sorosite is noticeably harder (Mohs 3.5-4 vs. 1.5); streak differs, so Sorosite leaves silver-white, Native Tin leaves white.
Often found alongside sorosite
Minerals reported to co-occur with sorosite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Cu₁₊ₓSn
- Mohs hardness
- 3.5-4
- Density
- 8.8-9.0 g/cm³
- Colors
- Streak
- Silver-white
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Hexagonal
- Crystal habit
- Massive, Anhedral Grains
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Placer Deposits, Alluvial Gravels
- Typical price
- $50-300 per specimen
Where rockhounds find sorosite
Classic worldwide localities
- Russia
- United States
Field-hunting tip
Look in placer deposits, alluvial gravels country, the host setting where sorosite typically forms. If you start seeing cassiterite, stannite, native tin in float, you are in the right ground. Field specimens usually show a massive, anhedral grains habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find sorosite on the map
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