You catch a glimmer out of the corner of your eye - you've found some coins, but not the standard gold coins used in the rest of Gielinor. These are made out of a strange purple metal you haven't seen before, and have succumbed to the grips of rust.
You're not sure if they'll be of any use, but it can't hurt to put them in your coin pouch just in case.

A variant of my standard RuneScape Gold Coin, specifically designed as if found in Daemonheim. I've provided one version with the standard backing, and an alternate version that instead uses the symbol of Bilrach and the Ring of Kinship.