الوصف

The gem has the characteristic of selective aborption to the white light,when the white light get through the gem,some wave will be aborbed,so we can use the spectroscope to view it.The selective aborption has something to do with the colored element.So the spectroscope is the key instrument to tell the true color from the artifical.Besides,we can know the name of gem by the spectrum for many gem can absorb the spectrum.such as:ruby,almandite,emerald,zircon,jadeite,peridot,

Chrysobery.FPS*3A prism spectroscope adopt excellent prism,high resolution, adjustable focus, easy to use.But please notice the following points:

I. Light source: Use the white light which has continuous spectrum,such as optic fiber illumination or compact torch.daylight can’t be used here.

II. Ways of illumination:Make sure the light go through the gem,then get through the slit of spectroscope.The longer distance the light go through gem,the stronger the aborption can be,and the aborption spectrum is more clear.So you can use two illuminations:internal reference and transilluminationtrans.

1.Steps of internal reference

This way fit for the transparent facet gem,steps are as follows

(1)put the sample against black background.

(2)Hold the light(such as compact torch) to gem in he left hand,the spectroscope in the right hand,make the slit direct to the light refleccted by the sample,then view the spectrum through ocular,adjust the position of the spectroscope till seeing the most clear spectrum.

2.Transillumination

This method is fit for transparent gem but not facet gem,and the semitransparent gem.Steps are as follows:

(1)Put the sample on the compact torch.Use a light barrier if the gem too small,put the sample on the suitable hole on the light barrier to avoid the other light.

(2)Hold the spectroscope in the right hand, then view the spectrum through ocular,adjust the position of the spectroscope till seeing the most clear spectrum.

III.Matters need attention

1.     Avoid hot and wet,and no vibration

2.     When there is a vertical line on the spectrum,it is caused by dust,use something to blow it,don’t use any washing liquid for it will destroy the slit.

3.     Don’t use hand to hold the sample,for the blood will cause a wave of **2nm

4.     Don’t take the instruments apart,we have already debugged.