Diamine Jack Frost is a blue fountain pen ink with red-ish pink sheen and blue shimmer.
The Diamine Blue Edition is a continuation of the 2019 Diamine InkVent calendar, with gorgeous glass bottles containing 50 mL of fountain pen ink, in what resembles an ornament box!
Shimmer inks are great fun but require a bit of care. Before filling, shake the bottle ever so gently (with the cap on). 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. Exercise good pen hygiene, use the pen often, and you will have a good time. Leave it sitting for too long, and you might have a clogged feed.