Chrysoberyl the name is from the greek meaning golden although is found in a range of colours rangeing from yellow to green. The gem varieties are amongst the worlds rarest gems with Alexandrite coming under this heading. Whilst nearly always faceted a cat eye cabochon is also found and the name only cats eye gem refers to this gem alone all others should have there name after cats eye I.E cats eye quartz. This is a hard wearing gem that makes it ideal for jewellers. Mohls hardness of 8-8.5 the refractive index for this gem is 1.746-1.763. Most depsoits of this gem are now worked out and the others finding less of gem quaility.