Urban Decay Studded is a neutral brown with a frost finish that is discontinued and retails for $18.00. In comparison, MAC Viva Glam Rihanna 2 is a warm brown with a frost finish that is limited edition and retails for $19.00.
MAC Viva Glam Rihanna 2 is 90% similar — it is lighter, less pigmented, warmer, glossier.