Opal

Description

Key Characteristics of Opal:

• Play-of-Color: The most distinctive feature of opal is its play-of-color, which refers to the shifting flashes of different colors across its surface. This effect is caused by the internal structure of the opal, which is made up of microscopic silica spheres that diffract light. The colors that appear can range from blues and greens to reds, oranges, and purples, often appearing as a rainbow-like display.
• Color: Opals come in a wide range of colors, including white, black, fire (red or orange hues), and boulder opal (which features a darker, often brown, background). The most valuable opals typically have vibrant play-of-color against a dark or black background, which enhances the brightness of the colors.
• Hardness: Opals are relatively soft compared to other gemstones, scoring 5.5 to 6.5 on the Mohs scale of hardness. This means they can be more prone to scratching and breaking, and they require more care and protection when set in jewelry.
• Clarity: Opals are typically opaque to semi-transparent. They can display inclusions, but unlike other gemstones, inclusions in opals do not usually diminish their value unless they significantly affect the stone’s integrity or appearance.
• Structure: There are two main types of opals:
  • Precious Opal: This type displays the play-of-color and is highly prized. It is typically transparent to translucent.
  • Common Opal: This type lacks the play-of-color and is opaque. While still beautiful, it is less valuable than precious opal.