Comparison · Igneous Rocks vs Quartz Family
Obsidian vs Smoky Quartz
Obsidian and Smoky Quartz are easy to confuse. Smoky Quartz is harder (Mohs 7) than Obsidian (Mohs 5.5), so Smoky Quartz will scratch Obsidian 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 Obsidian and Smoky Quartz
- Smoky Quartz is harder (Mohs 7) than Obsidian (Mohs 5.5), so Smoky Quartz will scratch Obsidian 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: Obsidian is translucent, Smoky Quartz is transparent.
- They overlap in black and brown, but Obsidian also comes in green and multicolored and Smoky Quartz also comes in gray.
- Well-formed crystals give it away: Obsidian is amorphous, Smoky Quartz is hexagonal.
Obsidian vs Smoky Quartz properties
| Property | Obsidian | Smoky Quartz |
|---|---|---|
| Type | Igneous Rocks | Quartz Family |
| Mohs hardness | 5.5 | 7 |
| Luster | vitreous | vitreous |
| Streak | White | White |
| Transparency | translucent | transparent |
| Specific gravity | 2.4 | 2.65 |
| Crystal system | amorphous | hexagonal |
| Common colors | Black, Brown, Green, Rainbow | Brown, Gray, Black |
| Rarity | common | common |
| Typical specimen value | $5–$100+ | $5–$150+ |
Which is more valuable?
Smoky Quartz is usually the more valuable of the two: a typical collector specimen runs about $30 against $20 for Obsidian, and premium Smoky Quartz can reach $150 or more.
About Obsidian
Obsidian is a naturally occurring volcanic glass formed from rapidly cooled lava. Its sharp edges made it invaluable for ancient tools and weapons.
About Smoky Quartz
Smoky quartz is a brown to black variety of quartz colored by natural irradiation. The national gem of Scotland, it ranges from light tan to nearly opaque black.
Obsidian vs Smoky Quartz FAQ
Is Obsidian the same as Smoky Quartz?
No. Obsidian is a igneous rock while Smoky Quartz is a quartz family. Smoky Quartz is harder (Mohs 7) than Obsidian (Mohs 5.5), so Smoky Quartz will scratch Obsidian 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 Obsidian from Smoky Quartz?
Smoky Quartz is harder (Mohs 7) than Obsidian (Mohs 5.5), so Smoky Quartz will scratch Obsidian 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: Obsidian is translucent, Smoky Quartz is transparent. They overlap in black and brown, but Obsidian also comes in green and multicolored and Smoky Quartz also comes in gray.
Which is harder, Obsidian or Smoky Quartz?
Smoky Quartz is harder: Mohs 7 against Mohs 5.5 for Obsidian.
Which is more valuable, Obsidian or Smoky Quartz?
Smoky Quartz is usually the more valuable of the two: a typical collector specimen runs about $30 against $20 for Obsidian, and premium Smoky Quartz can reach $150 or more.
