Unstable Ingots are an item from the 'Extra Utilities' mod. To craft one you will need an Iron Ingot, a Division Sigil and a Diamond.
-IMPORTANT NOTICE- As the name implies, Unstable Ingots are exactly that; unstable. Within 10 second of being crafted they WILL explode if not utilized immediately.
(Note: You must perform the activation ritual before using the division sigil.)