PROVIDENCE, R.I., Nov. 11, 2014 — Sapphire and ruby balls from Meller Optics Inc. are designed for a range of applications that require precise tolerances, such as medical devices and fiber optic lens systems. They are available in 42 metric and inch sizes, from 0.1 mm to 0.5 in. diameters, with 0.000025-in. sphericity and ±0.0001-in. basic diameter tolerance. They feature Moh 9 hardness and have surface finishes with an 80-20 scratch-dig rating, as well as a 2000 °C melting point.