Comparison · Quartz Family vs Silicate Minerals
Quartz vs Zoisite
Quartz and Zoisite are easy to confuse. Both sit near Mohs 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 Quartz and Zoisite
- Both sit near Mohs 7, so a scratch test alone will not separate them. Lean on luster, streak and heft instead.
- Zoisite feels noticeably heavier for its size (specific gravity 3.3 versus 2.65 for Quartz).
- Hold a thin edge to the light: Quartz is Transparent to translucent, Zoisite is transparent.
- They overlap in pink and gray, but Quartz also comes in clear, purple, yellow, black, and brown and Zoisite also comes in green and blue.
- Well-formed crystals give it away: Quartz is Trigonal, Zoisite is orthorhombic.
Quartz vs Zoisite properties
| Property | Quartz | Zoisite |
|---|---|---|
| Type | Quartz Family | Silicate Minerals |
| Mohs hardness | 7 | 6.5 |
| Luster | Vitreous, greasy on fracture surfaces | vitreous |
| Streak | White | White |
| Transparency | Transparent to translucent | transparent |
| Specific gravity | 2.65 | 3.3 |
| Crystal system | Trigonal | orthorhombic |
| Common colors | Colorless, White, Purple (amethyst), Yellow (citrine), Pink (rose), Brown/black (smoky) | Green, Pink, Blue, Gray |
| Rarity | common | uncommon |
| Typical specimen value | $5–$250+ | $12–$450+ |
Which is more valuable?
Zoisite is usually the more valuable of the two: a typical collector specimen runs about $70 against $35 for Quartz, and premium Zoisite can reach $450 or more.
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.
About Zoisite
Zoisite is a calcium aluminum silicate that occurs in striated prismatic crystals and massive aggregates. Best known through its blue-violet gem variety tanzanite and the pink variety thulite, it is both a metamorphic mineral and a notable gemstone.
Quartz vs Zoisite FAQ
Is Quartz the same as Zoisite?
No. Quartz is a quartz family while Zoisite is a silicate mineral. Both sit near Mohs 7, so a scratch test alone will not separate them. Lean on luster, streak and heft instead.
How can you tell Quartz from Zoisite?
Both sit near Mohs 7, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Zoisite feels noticeably heavier for its size (specific gravity 3.3 versus 2.65 for Quartz). Hold a thin edge to the light: Quartz is Transparent to translucent, Zoisite is transparent.
Which is harder, Quartz or Zoisite?
Quartz is harder: Mohs 7 against Mohs 6.5 for Zoisite.
Which is more valuable, Quartz or Zoisite?
Zoisite is usually the more valuable of the two: a typical collector specimen runs about $70 against $35 for Quartz, and premium Zoisite can reach $450 or more.
