Comparison · Quartz Family vs Silicate Minerals
Quartz vs Sugilite
Quartz and Sugilite are easy to confuse. Quartz is harder (Mohs 7) than Sugilite (Mohs 6), so Quartz will scratch Sugilite and not the other way round. It is about as hard as window glass: a knife barely marks it, while a steel file (Mohs 6.5) will. Below is a side-by-side comparison of their properties and the quick tests that separate them.
Key differences between Quartz and Sugilite
- Quartz is harder (Mohs 7) than Sugilite (Mohs 6), so Quartz will scratch Sugilite and not the other way round. It is about as hard as window glass: a knife barely marks it, while a steel file (Mohs 6.5) will.
- Hold a thin edge to the light: Quartz is Transparent to translucent, Sugilite is translucent.
- They overlap in purple, yellow, pink, and brown, but Quartz also comes in clear, black, and gray.
- Well-formed crystals give it away: Quartz is Trigonal, Sugilite is hexagonal.
Quartz vs Sugilite properties
| Property | Quartz | Sugilite |
|---|---|---|
| Type | Quartz Family | Silicate Minerals |
| Mohs hardness | 7 | 6 |
| Luster | Vitreous, greasy on fracture surfaces | vitreous |
| Streak | White | White |
| Transparency | Transparent to translucent | translucent |
| Specific gravity | 2.65 | 2.74 |
| Crystal system | Trigonal | hexagonal |
| Common colors | Colorless, White, Purple (amethyst), Yellow (citrine), Pink (rose), Brown/black (smoky) | Purple, Violet, Magenta, Pink, Brownish yellow |
| Rarity | common | rare |
| Typical specimen value | $5–$250+ | $15–$1200+ |
Which is more valuable?
Sugilite is usually the more valuable of the two: a typical collector specimen runs about $150 against $35 for Quartz, and premium Sugilite can reach $1200 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 Sugilite
Sugilite is a rare lithium-bearing cyclosilicate best known for its vivid purple to magenta gem material. It usually occurs as massive aggregates rather than crystals and is used as an ornamental and lapidary stone.
Quartz vs Sugilite FAQ
Is Quartz the same as Sugilite?
No. Quartz is a quartz family while Sugilite is a silicate mineral. Quartz is harder (Mohs 7) than Sugilite (Mohs 6), so Quartz will scratch Sugilite and not the other way round. It is about as hard as window glass: a knife barely marks it, while a steel file (Mohs 6.5) will.
How can you tell Quartz from Sugilite?
Quartz is harder (Mohs 7) than Sugilite (Mohs 6), so Quartz will scratch Sugilite and not the other way round. It is about as hard as window glass: a knife barely marks it, while a steel file (Mohs 6.5) will. Hold a thin edge to the light: Quartz is Transparent to translucent, Sugilite is translucent. They overlap in purple, yellow, pink, and brown, but Quartz also comes in clear, black, and gray.
Which is harder, Quartz or Sugilite?
Quartz is harder: Mohs 7 against Mohs 6 for Sugilite.
Which is more valuable, Quartz or Sugilite?
Sugilite is usually the more valuable of the two: a typical collector specimen runs about $150 against $35 for Quartz, and premium Sugilite can reach $1200 or more.
