Lethal Cosmetics Spirit is a cool purple with a metallic finish that is permanent and retails for $6.00. In comparison, Natasha Denona Amethyst (141M) is a cool purple with a sparkle finish that is discontinued and retails for $29.00.
Natasha Denona Amethyst (141M) is 80% similar — it is more shimmery, darker, cooler.