Imagine, you are a woman going out for the day to an important party. You are dressed beautifully, in your finest, you hair is beautifully done and you are sure to stand out from the crowd. You still have to choose the perfect necklace to finish the ensemble though. You want to stand out and make an impression, so you need something eye catching and different. You look at the collection of glass pendants you have and choose one made of shining dichroic glass. With that necklace reflecting the sun in so many colours, you are sure to make an impression!
When I took these dichroic glass pendants to show the children, they were really impressed by them. They had not seen glass which sparkled with so many colours or with what appeared to be so many textures. They were particularly impressed with the way the glass seemed to absorb and reflect all the light around it, making a stunning colourful display. The children were most surprised though to discover that dichroic glass is used in space ships. That elevated the glass from simply pretty to ‘totally awesome’ according to the boys.
Dichroic glass is a very special type of glass. It has lots of different layers of metals or oxides which build up a complex pattern and colour scheme. The main feature is that the colour which you first see, embedded in the glass is a completely different colour to the one which the glass reflects because of the way light is refracted in the glass. Depending on where you are standing when you look at the glass, the colour schemes subtly change, making it a stunning basis for ornaments and jewellery.
The word dichroic comes from a Greek word, dikhroos, which actually means two coloured. Although the invention of dichroic glass is often attributed to NASA, the ancient world also had this type of glass by at least the 4th century AD. This is when a Roman cup, known as the Lycurgus Cup, was created. This cup features glass which, when it is transmitting light appears red, but when it is reflecting light it appears green. This effect was created by adding very finely ground gold and silver to the glass. In more modern times though, dichroic glass began to be used for more scientific purposes. In the 1950s and 1960s NASA began to experiment with using dichroic glass to create optical filters. Metallic oxide layers are fused to the top of the glass (instead of being mixed through like the Lycurgus Cup) and can be used to filter light. These filters are very effective, but artisans also realised they could be very pretty and started using the same process to create art glass, including jewellery like the pendants I showed the children.