All crafting and artisanry using this skill follows the typical Tradecraft mechanics (including Specialization). Such practices typically use some form of Utility (tool, kit, workstation) to fabricate items. The Material Composition accessible varies by setting, technology, and crafter.
The basics of how the materials used in crafting are part of the craft knowledge. These include where the materials generally come from, how they are extracted or fabricated, transported, cultural significance, and the grades of quality. Deep material understanding – chemistry, biology, etc. – is not included. Incorporating elements that are prefabricated does not grant specific knowledge of making them.