Rune dust

'Rune dust can be made by using a hammer on a rune essence or pure essence stone to crack them into rune shards, and then grind these down in in a pestle and mortar.

Rune shards and rune dust appear in the Garden of Tranquility quest, when rune dust must be added to a plant cure potion to revive some badly damaged vines in Bernald's garden behind his house in south east Burthorpe.