Cassiterite is the primary ore of tin and is easily recognized by its extremely high specific gravity and adamantine luster. It often forms squat, dipyramidal crystals or dark, massive aggregates in hydrothermal veins associated with granitic rocks. Collectors prize it for its sharp crystal forms and characteristic heavy feel.
Is this cassiterite?
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 cassiterite with a known reference. Cassiterite sits at Mohs 6-7 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Cassiterite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Cassiterite typically shows a adamantine luster.
- 4Match the color rangeCompare against the expected color range: black, brown, reddish-brown, yellow, gray.
- 5Look at form & habitCrystal system: tetragonal. Typical habit: prismatic crystals, pyramidal, massive, granular, botryoidal.
Often confused with
Cassiterite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Streak differs — Cassiterite leaves white, Rutile leaves pale brown to yellow; luster reads adamantine on Cassiterite and metallic to adamantine on Rutile.
How to tell apart: Cassiterite is noticeably harder (Mohs 6-7 vs. 4-4.5); streak differs — Cassiterite leaves white, Wolframite leaves dark brown to black; luster reads adamantine on Cassiterite and submetallic to metallic on Wolframite.
How to tell apart: Cassiterite is noticeably harder (Mohs 6-7 vs. 3.5-4); streak differs — Cassiterite leaves white, Sphalerite leaves white to yellow-brown; luster reads adamantine on Cassiterite and resinous to submetallic on Sphalerite.
Often found alongside cassiterite
Minerals reported to co-occur with cassiterite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- SnO₂
- Mohs hardness
- 6-7
- Density
- 6.8-7.1 g/cm³
- Streak
- White
- Luster
- Adamantine
- Transparency
- Translucent
- Crystal system
- Tetragonal
- Crystal habit
- Prismatic Crystals, Pyramidal, Massive, Granular, Botryoidal
- Cleavage
- Imperfect
- Rarity
- Common
- Uses
- Ore, Collector, Decorative
- Host rock
- Granite Pegmatites, Hydrothermal Veins, Greisens
- Typical price
- $10-100 thumbnail, $50-500 cabinet specimen
Where rockhounds find cassiterite
13 mapped spotsClassic worldwide localities
- Bolivia
- China
- Malaysia
- Indonesia
- Cornwall, UK
- Russia
Field-hunting tip
Look in granite pegmatites, hydrothermal veins, greisens country — that is the host setting where cassiterite typically forms. If you start seeing quartz, topaz, tourmaline in float, you are in the right ground. Field specimens usually show a prismatic crystals, pyramidal, massive, granular, botryoidal habit, so train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in Alabama, North Carolina, Montana — start trip planning there.
Common questions
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Find cassiterite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
