Guyana Hindu Wedding Jewellery Collection 1

                             Sapphire             Guyana hindu Jewellery
By Aamir Mannan.

                              (Iron)

One of the most important spectra in the whole series for the practising gemmologist is that of sapphire, for it not only  proclaims the species of the stone, but also reveals whether it 
be natural or synthetic.The spectrum,which is due to iron, is seen at full strength in green sapphire and in varying strength in yellow sapphire,as has been described above.In blue sapphires the bands are again very variable in strength.Australian sapphires show all three bands quite strongly,while in Ceylon saphires,which contain very little iron only the 4500 band be seen and therefore shows at maximum strength in 

the direction of the optic axis.In a cut stone this direction may usually not be known,but it is worth while, if the bands is only very faintly seen, to turn the stone on edge and on end in attempt to see the band more strongly.A 'Polariod' disc turned to the correct angle over the eyepiece of the spectroscope may also help to increase the
apparent strength of the band.Passing light through a copper sulphate filter flask is here very helpful,enabling the observer to see any bands in the blue region with greater clarity.