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. Streak: white, pale brown, pale gray.
- 3Read the lusterHold the specimen under a strong light. Luster: adamantine to adamantine metallic, splendent; may be greasy on fractures.
- 4Match the color rangeCompare against the expected color range: black, brown, reddish-brown, yellow, gray, brownish black, colorless, green.
- 5Look at form & habitCrystal system: tetragonal. Typical habit: botryoidal, massive, prismatic.
Often confused with
Cassiterite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Cassiterite leaves white, pale brown, pale gray, Rutile leaves pale brown, yellowish brown; gray, greenish black with high nb–ta.
How to tell apart: Cassiterite is noticeably harder (Mohs 6-7 vs. 4.5); streak differs, so Cassiterite leaves white, pale brown, pale gray, Wolframite leaves reddish brown; luster reads adamantine to adamantine metallic, splendent; may be greasy on fractures on Cassiterite and submetallic on Wolframite.
How to tell apart: Cassiterite is noticeably harder (Mohs 6-7 vs. 3.5-4); streak differs, so Cassiterite leaves white, pale brown, pale gray, Sphalerite leaves pale brown to pale yellow and white; luster reads adamantine to adamantine metallic, splendent; may be greasy on fractures on Cassiterite and resinous to adamantine 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
- 6.98-7.01 g/cm³
- Streak
- White, pale brown, pale gray
- Luster
- Adamantine to adamantine metallic, splendent; may be greasy on fractures
- Transparency
- Transparent
- Crystal system
- Tetragonal
- Crystal habit
- Botryoidal, massive, prismatic
- Cleavage
- {100} imperfect, {110} indistinct; partings on {111} or {011}
- Rarity
- Common
- Uses
- Ore, Collector, Decorative
- Host rock
- In medium- to high-temperature hydrothermal veins and greisen, in granite, granite pegmatite, rhyolite; rarely in contact metamorphic deposits; in large alluvial placers
Where rockhounds find cassiterite
13 mapped spotsClassic worldwide localities
- Saxony, at Marienberg, Altenberg, Johanngeorgenstadt, Germany
- Cínovec (Zinnwald) and Horní Slavkov (Schlaggenwald), Czech Republic
- La Villeder, Morbihan, France
- Panasqueira and Cabreiros, Portugal
- Jos district, Nigeria
- Otjimbojo, Namibia
Field-hunting tip
Where it forms: In medium- to high-temperature hydrothermal veins and greisen, in granite, granite pegmatite, rhyolite; rarely in contact metamorphic deposits; in large alluvial placers. If you start seeing quartz, muscovite, wolframite in float, you are in the right ground. Typical habit: botryoidal, massive, prismatic. 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.
More cassiterite photos
Common questions
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Find cassiterite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
