A selection of natural diamonds - seen here in white (normal) light.
The diamonds fluoresce differently under long-wave ultra-violet radiation depending on their different impurity contents.
A ring containing small synthetic diamonds which phosphoresce after exposure to short-wave ultra-violet radiation.
A 1 mm natural octahedral diamond shows a seed crystal in the natural white-light photograph. Under long-wave ultra-violet light fluorescence can be seen in a central, possibly on account of different growth sectors having different impurity content.
This light pink diamond shows blue-green fluorescence under short-wave ultra-violet and pinkish fluorescence under long-wave ultra-violet radiation.
A yellow diamond shows bright green fluorescence along with visible sectors suggestive of HPHT treatment.
This is a ring with three diamonds. The outer two fluoresce more strongly under short-wave ultra-violet than under long-wave ultra-violet, which suggests they are synthetics.
Photographing diamond photoluminescence using a Gemetrix PL-Inspector
Bright green fluorescence of a natural green diamond is seen under long-wave u.v.