Electrum

Electrum is an alloy added by various mods. It is usually made by combining Silver and Gold either in dust form in a crafting grid or combine the dusts or ingots in an Induction Smelter or Alloy Smelter.

Immersive Engineering
Electrum is used to make various machines and components, such as Heavy Engineering Blocks and LV Wire Coils.

Thermal Foundation
Electrum can be made in Thermal Foundation by mixing Gold and Silver dust.

Then smelt the resulting blend into Electrum ingots.

Or else, the electrum ingots can be created directly in an Induction Smelter.