Epidote

Color due to iron and manganese. The intense absorption up to 500nm. in this rare red variety of epidote masks any evidence of the iron band normally detected in the pale greenish brown stones centered at 455nm. often accompanied by a weaker band at 475nm. However, in this red specimen a fairly wide band appears centered at 550nm

Color due to iron and manganese. The intense absorption up to 500nm. in this rare red variety of epidote masks any evidence of the iron band normally detected in the pale greenish brown stones centered at 455nm. often accompanied by a weaker band at 475nm. However, in this red specimen a fairly wide band appears centered at 550nm. When the lighter gamma ray is isolated the much weaker absorption in the green is evidence of the lighter color in the pleochroic effect

Color due to iron. This strongly pleochroic dark brown gemstone may require the use of a polarizing filter to transmit sufficient light from the lighter brown alpha ray. The main feature is a strong band centered at 458nm. in the deep blue with a weaker one on the long wave side at 475nm. which strengthens as the greenish beta ray is located. The darker brown gamma ray can absorb all up to about 500nm. and may obscure the bands referred to here.