Friday, April 6, 2012

What is Dichroic Glass?

Dichroic glass has become very popular over the last couple of years. As I have visited stores here and there, these unusual and sometimes mesmerizing pieces of  art can be found in necklaces, pendants, earrings, rings and even wall hangings. Choosing a favorite, as I like to do when seeing a displayed array of items, can be tricky. No two are alike though may be similar. I think the pieces that fascinate me the most are the dramatic color changers. No wonder dichroic glass is also referred to as "chameleon glass."

Where did it come from?
Modern dichroic glass is available as a result of a materials research carried out by NASA and its contractors, who developed it for use in dichroic filters. However, it can also be traced back to the 4th century AD as seen in the Lycurgus Cup, which resides in a museum in London.  The picture on the left depicts the cup in normal light. The picture on the right depicts the cup photographed with a flash, showing it's green color though no light is coming through it. It is the only complete Roman glass object made from this type of glass, and the one exhibiting the most impressive change in color.

The main characteristic of dichroic glass in that it has a particular transmitted color and a completely different reflected color, as certain wavelengths of light either pass through or are reflected. This causes an array of color to be displayed, and the colors shift depending on the angle of view. Dichroic glass is an example of thin-film optics.

How is it made? 
Multiple ultra thin layers of different metals, such as gold or silver and the oxides of such metals - titanium, chromium, aluminium, zirconium, magnesium, or silica - are vaporised by an electron beam in a vacuum chamber. The vapor then condenses on the surface of the glass in the form of a crystal structure. A protective layer of quartz is sometimes added. The finished glass can have as many as 30 to 50 layers of these materials, yet the total thickness can be 30 to 35 millionths of an inch. The coating that is created is similar to gemstones and, by careful control of thickness, different colors may be obtained. A plate of dichroic glass can be fused with other glass in multiple firings. Due to variations in the firing process, results can not be exactly predicted, so each piece of glass is unique.

Making these amazing pieces is certainly not a "Do-It-Yourself" project.  Limited supply is due to the requirement for very high-tech equipment and skilled artisans.

Dichroic glass adds flash, pizazz, sparkle and intrigue. It is  recommended to wear one piece of dichroic jewelry at a time to attract attention, comments or perhaps conversation, as several pieces tend to overwhelm and take away the mystery and uniqueness in each piece.

Cliptomania.com offers non-pierced earrings that are made of dichroic glass. Cliptomania's owner, Candy Santo, noted she had a hard time catching a good photo as the shine and color changing kept blurring its outcome. See these and other beautiful earrings at www.cliptomania.com.