Precious stones optical support - has tube with bevelled surface on which stone rests for examination by transmitted light

A support is used for the examination of cut diamonds or other precious stones, pref. by illuminating them in the transmission mode. It has a bevelled surface (40) in a metallic tube (31) for a tube made from some other material impermable to light whose cross section and the circumference of the precious stone under examination are similar. The internal dimension of the tube is slightly less than that of the precious stone and the tube is fitted with a grooved collar (38). The support is able to be rotated through 360 or more and can be inclined, in some cases, up to 45, thus making it possible to examine the precious stone under every angle of interest.