Simply Mythril

Lightweight mod that adds Mithril as an intermediate material between iron and diamond.

The main feature of Mithril is the ability to sequentially upgrade tools from iron to netherite while preserving all enchantments!

Mithril ore generates in the Overworld at elevations from -46 to +46 blocks, with the highest concentration at level zero. When mined, it drops raw Mithril that can be smelted into nuggets. "Why nuggets?" Because upgrading an iron tool to a mithril one requires only one ingot!

Mithril Enchanting Table (version 1.2.0+) The Mithril Enchanting Table allows enchanting items in the early game stages! It's less powerful than a regular enchanting table but doesn't require diamonds to craft.