Comparison · Minerals vs Quartz Family
Dumortierite vs Quartz
Dumortierite and Quartz are easy to confuse. Both sit near Mohs 7–8.5, 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 Dumortierite and Quartz
- Both sit near Mohs 7–8.5, so a scratch test alone will not separate them. Lean on luster, streak and heft instead.
- Dumortierite feels noticeably heavier for its size (specific gravity 3.3–3.4 versus 2.65 for Quartz).
- Hold a thin edge to the light: Dumortierite is Translucent to opaque, Quartz is Transparent to translucent.
- They overlap in purple, brown, and pink, but Dumortierite also comes in blue and Quartz also comes in clear, yellow, black, and gray.
- Well-formed crystals give it away: Dumortierite is Orthorhombic, Quartz is Trigonal.
Dumortierite vs Quartz properties
| Property | Dumortierite | Quartz |
|---|---|---|
| Type | Minerals | Quartz Family |
| Mohs hardness | 7–8.5 | 7 |
| Luster | Vitreous, silky when fibrous | Vitreous, greasy on fracture surfaces |
| Streak | White | White |
| Transparency | Translucent to opaque | Transparent to translucent |
| Specific gravity | 3.3–3.4 | 2.65 |
| Crystal system | Orthorhombic | Trigonal |
| Common colors | Blue, Violet-blue, Brownish, Pink (rare) | 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 Dumortierite, and premium Quartz can reach $250 or more.
About Dumortierite
Dumortierite is an aluminum borosilicate mineral crystallizing in the orthorhombic system, best known for its intense blue to violet-blue color caused by trace iron and titanium substitutions. It typically forms fibrous, needle-like crystal aggregates within metamorphic rocks rich in aluminum, such as schists and gneisses subjected to high temperature and pressure. Its deep, saturated blue color has made it a popular but often misidentified substitute for lapis lazuli and sodalite in ornamental carvings.
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.
Dumortierite vs Quartz FAQ
Is Dumortierite the same as Quartz?
No. Dumortierite is a mineral while Quartz is a quartz family. Both sit near Mohs 7–8.5, so a scratch test alone will not separate them. Lean on luster, streak and heft instead.
How can you tell Dumortierite from Quartz?
Both sit near Mohs 7–8.5, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Dumortierite feels noticeably heavier for its size (specific gravity 3.3–3.4 versus 2.65 for Quartz). Hold a thin edge to the light: Dumortierite is Translucent to opaque, Quartz is Transparent to translucent.
Which is harder, Dumortierite or Quartz?
Dumortierite is harder: Mohs 7–8.5 against Mohs 7 for Quartz.
Which is more valuable, Dumortierite or Quartz?
Quartz is usually the more valuable of the two: a typical collector specimen runs about $35 against $20 for Dumortierite, and premium Quartz can reach $250 or more.
