Black Spinel faceted rondelles measure approximately 2.5mm to 3mm in diameter, the beads have a sub-adamantine luster which is slightly lower than diamond but above most other gems, the high luster provides exceptional refraction of light for brilliance, the cut and polish are of excellent quality producing a symmetrical rondelle, these Black Spinel beads are opaque with no internal characteristics , and the metallic coating adds an even higher level of brilliance to resemble create a `black diamond-like` gemstone.