In vanilla, a Shovel is a tool used to break dirt-based blocks faster. They are required to dig Gravel Ores.
The Iron Ingot can be also be any one of the vanilla material: wood planks, cobblestone, gold ingot, and diamond. In Hexxit, new materials are introduced to replace the iron ingot, such as Livingmetal and Biomass. There also is Bloodwood, Fusewood, Ghostwood, Darkwood, and Quartz Shovel. Each of the previous mentioned woods require sticks from their respective types in the recipe. The quartz shovel requires any quartz block in place of the iron ingot and the sticks must be of the ghostwood type.