Swiss Blue Topaz is a variety of topaz recognized for its distinctive blue hue. Here are some characteristics of Swiss blue topaz:
1. **Color:**
- Swiss Blue Topaz has a vibrant shade of blue, which can range from a light, bright blue to a deeper, darker blue. Its colour is often associated with clear skies.
2. **Clarity:**
- Topaz is often a transparent and crystalline semi-precious stone. However, there may be inclusions or impurities within the crystals, and these can affect the clarity of the stone.
3. **Hardness:**
- Topaz is a hard stone with a hardness of 8 on the Mohs scale. This makes topaz a good choice for everyday jewellery as it is quite scratch resistant.
4. **Use in jewellery:**
- Due to its attractive colour and hardness, Swiss blue topaz is often used in jewellery such as rings, earrings, necklaces and bracelets. The stone can be worked into various shapes including round, oval, cushion or pear.
5. **Treatments:**
- Blue topaz is obtained by treating white topaz to improve its colour or clarity. Following the treatment a change in the molecular structure of the crystal occurs, it becomes blue in the case of irradiation treatment or by impregnation of the outside of the crystal with oxide in the case of diffusion treatment.