Opal is admired for its gorgeous play-of-color that is unlike any other gem!
High quality black opals are amongst the most valued gemstones in the world! Their distinct play-of-color have been admired for centuries. It was once believed that opals were made of lightning and fell from the sky during thunderstorms. Historically, the majority of high quality opals have been mined in Australia, but can also be found in countries like Ethiopia, Mexico, and the United States.
Birthstone of October
Opal is the official birthstone of October. The ancient Greeks believed that opals prevented disease and held the powers of prophesy. Their silica structures are comprised of up to 20% water. Some opals (typically those mined in Ethiopia) are considered to be "hydrophane," meaning they absorb water.
The value of opal varies greatly based on many factors, the most important being the play-of-color. Play-of-color is defined by the patterns of color flashes seen within the opal. If an opal has a beautiful display of colors, its value will increase dramatically.
Another important factor is locality. Typically, opals mined in Lightning Ridge, Australia have a premium to them. This is due to Australia's extensive history of mining the gems, along with the physical properties of the opals.
Background color and carat weight also play a big role in value. Black opals are the most sought after because their background color helps the play-of-color become more visible. The least expensive opals can go for as little as $1 per carat while the most expensive can go for as high as $20,000 per carat.