Black Grape Manicure How-To (An Easy Fall and Thanksgiving / Beaujolais Nouveau Mani Tutorial Using Colors You Probably Already Have). An opaque, dark navy cream polish. (I used the navy polish from the Nail Rock Velvet Manicure kit in "Velvet Navy".). An opaque, dark purple cream, about a shade lighter than your dark navy. I used a dark purple limited edition I bought a couple of years ago- OPI “Sapphire in the Snow”.). Nail Rock Velvet Navy, OPI Sapphire in the Snow. Photo: Randi Reed / Cosme-Haul.