English 中文   Site Map

Earth Materials
Minerals | Rocks

Mineral Color
Pseudochromatic Color

Pseudochromatic colors are not caused by any actual color in the mineral, but by physical or optical effects on thin surface layers of the mineral.

Iridescence is an interference of light reflected from the mineral surface producing a spectrum of colors at different angles. The iridescent tarnish layers of the mineral Bornite is an example.


Tarnishes to an amazing green-blue after exposure to the air.
Size: (Right) 8 cm / (Left) 4 cm

Crystal within crystals