Hi Lindy, dichroic glass is lovely and the effect is cause by the prismatic effect built into the glass itself. Wikipedia has an explanation:-
The brilliant dichroic optical properties of dichroic glass are
the result of multiple micro-layers of metal oxides. These
thin layers of oxides have a total thickness of three to five
millionths of an inch.
NASA developed dichroic glass for use in face shields in space
suits. Multiple ultra-thin layers of different metals (gold,
silver, titanium, chromium, aluminium, zirconium, magnesium,
silicon) are applied to the surface of the glass. The glass is
then kiln fired at extreme temperatures in a vacuum.
The resulting plate of dichroic glass can then be fused with
other glass in multiple firings. Certain wavelengths of light
will either pass through or be reflected, causing an array of
colour to be visible. Due to variations in the firing process,
individual results can never be exactly reproduced; each piece
of fused dichroic glass is unique and no two pieces are ever
the same.
From Wikipedia, the free encyclopedia
HTH!
Tanya
