Conoscope FTP-ZG

This is one of the useful tool to observe the interference pattern of the gemstones. Also this is the important accessory of bench polariscope.

The conoscope, is an accessory tool to the polariscope. It allows visualizing the optical axes of a birefringent and transparent mineral.

Fist you observe your specmien under the polariscope. Find the interference colors of the optical axis C. Then put the conoscope in place, between the polarizing filters above the stone. Here you will discover the axes. Note that at least one facet needs to be exactly perpendicular to the optical axis, oterhwise you will not see the axes. When observing a cobochon or a spere the axes are easier to find.

Quartz is the only optical actif mineral and shows a typical bulls eye effect. Also you may discover if the quartz is left or right turning.