Daimond Ring.
By Aamir Mannan.
DIAMOND (STRUCTURE) Jewellery
Most diamonds show a narrow absorption band at 4I55 A in the deep violet which, when seen,is diagnostic for diamond.In 'Cape' stones this is very intense, and may be accompanied by five weaker bands at 4780,4650,45I0,4350,and 4230 A in the blue and violet.Of these weaker bands the 4780 band is the
most prominent.Diamonds of the 'brown' series may show a fine line in the blue-green at 5040 A with fainter lines at 5370 and 4980 A,but these are very difficult to see.On the whole,stones showing a 'Cape'
spectrum have a blue fluorescence under ultra-violet light,while diamonds of the brown series have a green fluorescence. A blue (copper sulphate ) filter will be found to make lines in the deep violet more easy to observe. It is worth nothing that light is most easily transmitted through a diamond in the direction of the gridle. The stone should be held in this position by
tweezers or on a glass plate with the aid of a small ball of plasticine. Alterations in the absorption spectrum of diamond induced by bombardment are described in the chapter on diamond.
By Aamir Mannan.
DIAMOND (STRUCTURE) Jewellery
most prominent.Diamonds of the 'brown' series may show a fine line in the blue-green at 5040 A with fainter lines at 5370 and 4980 A,but these are very difficult to see.On the whole,stones showing a 'Cape'
spectrum have a blue fluorescence under ultra-violet light,while diamonds of the brown series have a green fluorescence. A blue (copper sulphate ) filter will be found to make lines in the deep violet more easy to observe. It is worth nothing that light is most easily transmitted through a diamond in the direction of the gridle. The stone should be held in this position by
tweezers or on a glass plate with the aid of a small ball of plasticine. Alterations in the absorption spectrum of diamond induced by bombardment are described in the chapter on diamond.
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