A conoscope rod is also referred to as an optic figure sphere or an interference sphere. It's used in gem identification to help determine if a double refractive stone's optic character is biaxial or uniaxial. To locate an optic figure using a conoscope you would first set your polariscope to the dark crossed position, rotate your stone until you see interference (iridescent) colors or locate the brush, then place your conoscope on the interference color area or the narrowest part of the brush. This test is commonly done to help separate two double refractive stones with similar appearances or refractive index.
- Sphere Diameter: 10.0mm
- Keep sphere clean and free of oils and residue
- Store rod safely to prevent chips to its sphere