J. Herbin 1798 Amethyste de l’Oural (Ural Mountain Amethyst) is a deep purple ink with silver shimmer. 

Because of the particles in this ink that give it is beautiful colors, Lemur Ink recommends shaking the bottle ever so gently (with the cap on) before filling your fountain pen. Prior to writing, gently rock, roll, or twirl your pen in your hand (see: Iceman, Top Gun, 1986) to mix the particles that may have settled. Some users of this ink may experience feed clogging if left unused for a period of time. Exercise caution and practice good pen hygiene when using any shimmering ink.