Here is a beautiful handmade one of a kind reversible necklace with Dichroic glass, set in Sterling Silver,

Size - 31mm x 21mm x 7mm
length - 18 inches
material - Sterling Silver - Glass - Brass

Dichroic glass is glass containing multiple micro-layers of metal oxides which give the glass dichroic optical properties. The invention of dichroic glass is attributed to NASA and its contractors, who developed it for use in dichroic filters for space masks. It is also used in glass filters for dental lighting.

Recently dichroic glass has become available to artists through dichroic coating manufacturers.

The main characteristic of dichroic glass is that it has a 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. The colors shift depending on the angle of view, and the quality of the light.

Basically it reflects and refracts light transmitting the opposite colors of the spectrum at the same time.