Crystal opal is the type of opal most people traditionally recognize. The body of crystal opal is transparent, allowing the play of color to shine through. The fire (play of color) in crystal opals is generally categorized into two main types:
- Red-dominant fire is classified as red crystal opal
- Blue-green dominant fire is classified as blue-green crystal opal
While we use simple terms to describe opal colors, the richness of their fire far exceeds what words can capture:
- High-quality red crystal opal: In addition to red fire, you can observe blue, green, golden yellow, and even purple flashes
- Blue-green crystal opal: Primarily displays blue and green fire
Forming a high-quality red crystal opal requires more time and stable geological conditions, resulting in:
- Lower production of red crystal opals
- Higher value, especially evident in the paradigm of black opals
Transparency and Value of Crystal Opals
The transparency of crystal opals can range from completely clear to semi-transparent. Factors affecting their value include:
- Body transparency: The clearer, the better
- Fire intensity: Stronger is more desirable
- Combination: Crystal opals with high transparency and intense fire are the most precious
Due to the vast differences in crystal opal quality, their price range is equally wide, from affordable hundreds to high-end collector's jewelry pieces.
Characteristics of Crystal Opals
The term "crystal" can be misleading, as crystal opal is not a type of crystal. Its characteristics include:
- It's a hydrated amorphous form of silica, not a crystalline structure
- No symmetry or regular geometric shape
- Formation is limited by geographical space
- Often mixed with other minerals
- Cutting and polishing are challenging
Understanding these characteristics of crystal opals helps us better appreciate this unique gemstone and make informed decisions when purchasing. Whether you're drawn to the fiery reds or the cool blue-greens, each crystal opal offers a mesmerizing display of nature's artistry.