RocksdayEuclase vs Topaz
To tell Euclase from Topaz: Topaz is heavier and usually a stronger yellow, pink or blue.
A hard beryllium silicate, usually pale blue or colorless, with one perfect cleavage that makes it risky to set in jewelry.
Photo: Robert M. Lavinsky, CC BY-SA 3.0
A fluorine-bearing silicate and the Mohs reference for hardness 8. Crystals are often clear with sharp, diamond-shaped cross-sections.
Photo: Parent Géry, CC BY-SA 3.0
Key differences
- Topaz is heavier and usually a stronger yellow, pink or blue.
Side by side
| Property | Euclase | Topaz |
|---|---|---|
| Type | Mineral | Mineral |
| Mohs hardness | 7.5 | 8 |
| Luster | Vitreous | Vitreous |
| Streak | White | White |
| Colors | Blue, Green, White, Clear | Clear, Yellow, Orange, Blue, Pink |
| Crystal system | Monoclinic | Orthorhombic |
| Specific gravity | 3–3.1 | 3.49–3.57 |
| Formula | BeAlSiO₄(OH) | Al₂SiO₄(F,OH)₂ |
| Found in | Minas Gerais, Brazil; Chivor, Colombia | Ouro Preto, Brazil; Topaz Mountain, Utah |
Properties that are the same for both are grayed out.
How to identify euclase
- Pale blue or colorless prismatic crystals.
- Hardness 7.5, but it splits on a flat plane if bumped.
- Heavier than beryl of the same size.
Crystal system: Monoclinic
Full Euclase guide →How to identify topaz
- Harder than quartz (8).
- One perfect cleavage across the crystal — flat, mirror-like breaks.
- Feels heavier than quartz of the same size.
- Prisms with lengthwise striations.
Crystal system: Orthorhombic
Full Topaz guide →More comparisons
Frequently asked questions
What is the difference between euclase and topaz?
Euclase is a mineral with a Mohs hardness of 7.5 and a vitreous luster, usually blue, green, white or colorless. Topaz is a mineral with a Mohs hardness of 8 and a vitreous luster, usually colorless, yellow, orange, blue or pink.
How can you tell euclase from topaz?
Topaz is heavier and usually a stronger yellow, pink or blue.
Could you tell them apart from a blurry close-up?
Play today's Rocksday