Gjall

As defined by the Cleasby & Vigfusson Old Norse to English dictionary:

gjall

n, cinders from a smith’s furnace.

Possible runic inscription in Younger Futhark:ᚴᛁᛅᛚᛚ
Younger Futhark runes were used from 8th to 12th centuries in Scandinavia and their overseas settlements