Electrum is an alloy added by Thermal Foundation. It consists of Gold and Silver in a 1:1 ratio.
Electrum can also be made using Ingots instead of Pulverized metals in an Induction Smelter.
Electrum can be used to craft tools and armor. It is also a common ingredient for crafting the third tier of machines and devices in Thermal Expansion. With Redstone Arsenal installed, Electrum can be infused with Destabilized Redstone to create Fluxed Electrum.