166 SHIMMERING COLOUR
Shimmering colour
P
lay of colour is caused by the interference
of light interacting with a gemstone. Depending
on the internal structure of the gem, light waves
bounce off different layers, creating interference. The
result is a shimmer of surface or internal colour.Precious opal
An opal’s amazing play of colour is
produced by tiny spheres of silica
gel, which reflect and diffract light.Aquamarine
This light blue aquamarine has been
faceted to maximize the interplay of
light in its transparent interior.Ammolite
A unique combination of high temperature
and pressure produces iridescent colouring
in these rare organic gemstone fossils.Mystic topaz
This type of gem is a recent innovation, dating back to the late 1990s.
The colour effects are artificial, produced by adding a thin, chemical
coating to a white topaz; the colours change when the gem is tilted.166-167_FEA_Shimmering_colour.indd 166 19/05/2016 14:44