Opal’s shifting play of kaleidoscopic colors is unlike any other gem. In ancient Rome the gem symbolized love and hope. The Romans gave it a name -opalus_ that was synonymous with "precious stone".
Play of color is the number one quality factor when considering an opal . Play-of-color occurs when light interacts with opal's orderly arrangement of silica spheres. As the light waves travel, they diffract or bend. As they bend they break up into spectral colors, causing play-of-color. At the higher end of the opal market, brilliant colors and intricate patterns engage the eye. Fainter background colors and spectral hues are valued less but still beautiful.
With an opal, clarity is its degree of transparency and freedom from inclusions. The clarity of an opal can range all the way from completely transparent to opaque. Experts prize different levels of clarity for different opal types.
The cutter considers an opal’s color, pattern, and clarity when considering the finished gem. As with many top-quality stones, exceptional opals might not be cut to standard shapes and sizes. Domed surfaces give the best play-of-color.
Opal has high water content. Although most opal is cured to make sure it won’t crack, it’s never a good idea to subject your opal to very dry or hot conditions. Opal is a gem suitable for jewelry but requires care when wearing to not scratch or break the stone. Warm soapy water is always safe and the best way to cleanse your opal.