Onyx is a deep black with neutral undertones and flecks of silver sparkle over a matte finish. This shade was least like the rest of the shades in the palette, as the base was noticeably more matte and drier with a chalkier feel overall. The silver sparkles did not translate well to the lid, so this ended up appearing more like a matte, black eyeshadow than a sparkling one. It had medium color payoff that was buildable to semi-opaque coverage with two to three layers. The eyeshadow started to fade on me after eight hours of wear.