Brief Opal History
What could be more magical than the opal? The only gemstone to exhibit all spectral colors, it is truly a wonder to behold. Ancient Greeks believed that opal was a talisman from disease and Middle Eastern legend claims that opals fall to earth in flashes of lightning. The silica spheres in an opal’s structure causes light to show "play-of-color," shifting flashes of rainbow colors.
The most valuable opals have large, evenly distributed patches of vivid colors against a black body color. Today, the color red is the most prized opal hue. Most U.S. jewelry stores sell white opal, which is usually less expensive. Some pieces of opal are too thin to safely set in jewelry, which is why a sliver of opal is attached to a backing, such as glass, chalcedony or plastic to increase durability.
Philippe Medawar cautions potential opal purchasers that some opals have undergone various treatments, which makes them unstable and more vulnerable to durability and cleaning concerns.
Opals contain a small percentage of water and when exposed to intense heat, dehydration and cracking can occur. Dry, hot environments and sudden temperature changes can cause crazing (minute fractures). If you are wearing an opal ring in the heat of Arizona’s Sonoran Desert, do not thrust your hands under cold running water (put your head under instead). Do not store opals in airtight containers or safety deposit boxes as the dry air will result in a loss of moisture in the opal’s structure. Do not store opals in a bureau near a heat vent. Store opals in a soft-sided compartment away from other jewelry items. If you’d like more information on fine jewelry storage, click here.
To protect your opal and keep it looking its best, do not use an ultrasonic machine. The high heat, vibration and chemicals will harm your opal, causing dehydration and crazing (minute fractures) and could fracture the opal. For at-home cleaning, use a soft-bristled brush with warm, soapy water.
Philippe Medawar welcomes those with additional opal inquiries at his 28th Street showroom in Grand Rapids, Michigan.