Comparison · Semi-Precious Stones
Garnet vs Iolite
Garnet and Iolite are easy to confuse because both are semi-precious stones. 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 Garnet and Iolite
- Both sit near Mohs 7, so a scratch test alone will not separate them. Lean on luster, streak and heft instead.
- Garnet feels noticeably heavier for its size (specific gravity 3.8 versus 2.6 for Iolite).
- They overlap in purple, but Garnet also comes in red, orange, green, and brown and Iolite also comes in blue and gray.
- Well-formed crystals give it away: Garnet is cubic, Iolite is orthorhombic.
Garnet vs Iolite properties
| Property | Garnet | Iolite |
|---|---|---|
| Type | Semi-Precious Stones | Semi-Precious Stones |
| Mohs hardness | 7 | 7 |
| Luster | vitreous | vitreous |
| Streak | White | White |
| Transparency | transparent | transparent |
| Specific gravity | 3.8 | 2.6 |
| Crystal system | cubic | orthorhombic |
| Common colors | Red, Orange, Green, Purple, Brown | Violet-Blue, Blue, Gray |
| Rarity | common | uncommon |
| Typical specimen value | $10–$3000+ | $30–$800+ |
Which is more valuable?
Typical specimens of Garnet and Iolite trade in a similar range, around $100.
About Garnet
Garnet is a group of silicate minerals that share similar crystal structures. While red garnets are most common, they occur in every color except blue.
About Iolite
Iolite is the gem variety of cordierite, showing strong pleochroism—appearing different colors from different angles. Vikings may have used it for navigation.
Garnet vs Iolite FAQ
Is Garnet the same as Iolite?
No. Both are semi-precious stones, but they are distinct species with different hardness, streak or luster. 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 Garnet from Iolite?
Both sit near Mohs 7, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Garnet feels noticeably heavier for its size (specific gravity 3.8 versus 2.6 for Iolite). They overlap in purple, but Garnet also comes in red, orange, green, and brown and Iolite also comes in blue and gray.
Which is harder, Garnet or Iolite?
They are about equally hard, both near Mohs 7.
Which is more valuable, Garnet or Iolite?
Typical specimens of Garnet and Iolite trade in a similar range, around $100.
