Sapphire and ruby balls from Meller Optics have utility in lens systems
A full line of sapphire and ruby balls for use as fiber-optic and endoscope lens systems come with a calibration certificate validating diameter and sphericity. They have Mohs 9 hardness and surface finishes of 0.008 to 0.01 μm Ra, and are available in diameters from 0.1 mm to 0.5 in.
Meller Optics
Providence, RI