Gold is a bright yellow metal from Vanilla Minecraft that is commonly used to make gold tools. However, Gold can't be used to make Tinker's Construct tools.
It's only uses in Tinkers Construct are as a replacement for Aluminum Brass for making casts or as part of the crafting of the Knapsack. Gold can be melted down like all metals to get double from ore, or can be obtained as a drop from Zombie Pigmen.
In its liquid form, it can be poured onto various items to make their golden forms, such as carrots, apples, and heads.