Primeval Lyrium Rune

A rare, one-of-a-kind weapon rune crafted in Act III by Sandal after Varric's personal quest Haunted. The rune increases the attack speed of the weapon it is bound in. The exact % increase in attack speed varies with the quality of the weapon, with a 35% increase in top-tier weapons like Limbtaker.

Obtaining
The rune can only be obtained in Act III, after completing the main quest On The Loose. Talk to Varric in the Hanged Man to initiate a new personal quest, Haunted, and investigate recent claims of "paranormal activity" in Bartrand's former estate. Near the end of the quest, a choice will be presented: allow Varric to keep a fragment of the lyrium idol Bartrand claimed, or give the lyrium shard to Sandal for "disposal".

Sandal will then craft the Primeval Lyrium Rune.

After Varric's personal quest in Act 3, if the shard of the lyrium idol is taken to Sandal he will forge a Primeval Lyrium Rune that increases the attack speed of any weapon it's place in.