Comparison · Minerals vs Quartz Family
Cassiterite vs Quartz
Cassiterite and Quartz are easy to confuse. Both sit near Mohs 6–7, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Below is a side-by-side comparison of their properties and the quick tests that separate them.
Key differences between Cassiterite and Quartz
- Both sit near Mohs 6–7, so a scratch test alone will not separate them. Lean on luster, streak and heft instead.
- Streak color differs: Cassiterite leaves a white to grayish brown streak on unglazed porcelain, Quartz leaves white.
- Luster is different: Cassiterite is adamantine to submetallic while Quartz is vitreous, greasy on fracture surfaces.
- Cassiterite feels noticeably heavier for its size (specific gravity 6.8–7.1 versus 2.65 for Quartz).
- Hold a thin edge to the light: Cassiterite is Translucent to opaque, Quartz is Transparent to translucent.
- They overlap in brown, black, yellow, and gray, but Cassiterite also comes in red and Quartz also comes in clear, purple, and pink.
- Well-formed crystals give it away: Cassiterite is Tetragonal, Quartz is Trigonal.
Cassiterite vs Quartz properties
| Property | Cassiterite | Quartz |
|---|---|---|
| Type | Minerals | Quartz Family |
| Mohs hardness | 6–7 | 7 |
| Luster | Adamantine to submetallic | Vitreous, greasy on fracture surfaces |
| Streak | White to grayish brown | White |
| Transparency | Translucent to opaque | Transparent to translucent |
| Specific gravity | 6.8–7.1 | 2.65 |
| Crystal system | Tetragonal | Trigonal |
| Common colors | Brown, Black, Reddish brown, Yellow, Gray | Colorless, White, Purple (amethyst), Yellow (citrine), Pink (rose), Brown/black (smoky) |
| Rarity | common | common |
| Typical specimen value | $2–$150+ | $5–$250+ |
Which is more valuable?
Quartz is usually the more valuable of the two: a typical collector specimen runs about $35 against $20 for Cassiterite, and premium Quartz can reach $250 or more.
About Cassiterite
Cassiterite is tin oxide, SnO2, and has been the principal ore of tin since the Bronze Age. It crystallizes in the tetragonal system, typically as reddish-brown to black prismatic or pyramidal crystals with an adamantine luster and exceptionally high density for a nonmetallic-looking mineral. Its resistance to weathering means it survives erosion intact and concentrates in stream gravels as placer tin.
About Quartz
Quartz is silicon dioxide, SiO2, one of the most abundant minerals in Earth's continental crust, crystallizing in the trigonal division of the hexagonal crystal system with a hardness of 7 that makes it a standard reference point on the Mohs scale. Its six-sided prismatic crystals, often terminated by pyramidal points, are among the most recognizable crystal shapes in mineralogy. Quartz occurs in nearly every rock type and geologic setting, from granite pegmatites to sedimentary sandstones to hydrothermal veins.
Cassiterite vs Quartz FAQ
Is Cassiterite the same as Quartz?
No. Cassiterite is a mineral while Quartz is a quartz family. Both sit near Mohs 6–7, so a scratch test alone will not separate them. Lean on luster, streak and heft instead.
How can you tell Cassiterite from Quartz?
Both sit near Mohs 6–7, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Streak color differs: Cassiterite leaves a white to grayish brown streak on unglazed porcelain, Quartz leaves white. Luster is different: Cassiterite is adamantine to submetallic while Quartz is vitreous, greasy on fracture surfaces.
Which is harder, Cassiterite or Quartz?
Quartz is harder: Mohs 7 against Mohs 6–7 for Cassiterite.
Which is more valuable, Cassiterite or Quartz?
Quartz is usually the more valuable of the two: a typical collector specimen runs about $35 against $20 for Cassiterite, and premium Quartz can reach $250 or more.
