Dichroic glass commonly called dichro for short is glass that bends light to reflect colors as a prism makes a rainbow. I will give you a hint as to how it is pronounced (dye-crow-ick) because I certainly didn't get it right the first time I tried it. The unique feature about this glass is that it doesn't use dyes, paints or any other kind of coloring agent to create it unique coloring but it is comprised of multiple micro-layers of metal oxides which gives it the ability to reflect colors. I thought because of how it gets its coloring that dichroic glass would be a fairly new but it actually dates back at least to the 4th century AD and is derived from Greek words “di” for two and “chroma” for color. The beautiful thing about dichroic glass is that it appears to have more than one color at the same time especially when viewed from different angles.
There are some that say that NASA contractors get credit for developing dichroic glass because they used it in the dichroic filters. It's pretty amazing to think that the glass that we can use to make jewelry can also be made into something that was adapted for use in satellite mirrors in the 1990's and also used for the re-entry tiles on space shuttles. As I already stated this glass is created from ultra thin micro layers of metal oxides such as titanium, aluminum, magnesium and silica just to mention a few that are vaporized by an electron beam in some type of a vacuum chamber. Once this happens the vapors condense on the surface of glass in a type of crystal structure. That is a very simplified definition of how dichroic glass is formed but I'm afraid the process that is used is way to technical for me to understand.
Dichroic glass is similar to the Italian process of making Murano glass and has been used in Italian styles of ornamentation for hundreds of years. I wasn't able to find out exactly when it became popular in our country for use in jewelry only that in the last decade it seems to be growing in popularity. One reason that I think this is so popular for making jewelry is that because of the process used to make this glass no two pieces every look identical. You would think that because of the process involved in making dichroic glass that it would be extremely expensive but I have seen some truly beautiful jewelry at a very reasonable price. If you are into jewelry that is unique be sure to check out items made from dichroic glass. One nice thing is that you never have to worry about running into someone wearing an identical piece because with each artist own style and the variances of the glass itself originality is a sure bet.