Comparison · Minerals vs Quartz Family
Andalusite vs Quartz
Andalusite and Quartz are easy to confuse. Both sit near Mohs 6.5–7.5, 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 Andalusite and Quartz
- Both sit near Mohs 6.5–7.5, so a scratch test alone will not separate them. Lean on luster, streak and heft instead.
- Andalusite feels noticeably heavier for its size (specific gravity 3.13–3.21 versus 2.65 for Quartz).
- They overlap in brown, gray, and pink, but Andalusite also comes in red and green and Quartz also comes in clear, purple, yellow, and black.
- Well-formed crystals give it away: Andalusite is Orthorhombic, Quartz is Trigonal.
Andalusite vs Quartz properties
| Property | Andalusite | Quartz |
|---|---|---|
| Type | Minerals | Quartz Family |
| Mohs hardness | 6.5–7.5 | 7 |
| Luster | Vitreous | Vitreous, greasy on fracture surfaces |
| Streak | White | White |
| Transparency | Transparent to translucent | Transparent to translucent |
| Specific gravity | 3.13–3.21 | 2.65 |
| Crystal system | Orthorhombic | Trigonal |
| Common colors | Reddish brown, Olive green, Gray, Pink | 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 Andalusite, and premium Quartz can reach $250 or more.
About Andalusite
Andalusite is an aluminum silicate, Al2SiO5, and one of three natural polymorphs sharing that exact formula along with kyanite and sillimanite. It crystallizes in the orthorhombic system as stout, nearly square prisms formed under low-pressure, moderate-temperature metamorphism. Its variety chiastolite, which displays a dark cross pattern in cross-section, makes it one of the more recognizable metamorphic minerals to casual collectors.
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.
Andalusite vs Quartz FAQ
Is Andalusite the same as Quartz?
No. Andalusite is a mineral while Quartz is a quartz family. Both sit near Mohs 6.5–7.5, so a scratch test alone will not separate them. Lean on luster, streak and heft instead.
How can you tell Andalusite from Quartz?
Both sit near Mohs 6.5–7.5, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Andalusite feels noticeably heavier for its size (specific gravity 3.13–3.21 versus 2.65 for Quartz). They overlap in brown, gray, and pink, but Andalusite also comes in red and green and Quartz also comes in clear, purple, yellow, and black.
Which is harder, Andalusite or Quartz?
They are about equally hard, both near Mohs 6.5–7.5.
Which is more valuable, Andalusite or Quartz?
Quartz is usually the more valuable of the two: a typical collector specimen runs about $35 against $20 for Andalusite, and premium Quartz can reach $250 or more.
