Topic on Talk:Materials
Actually, I added that tag. I thought it undesirable that Materials be listed on the Material category page, so didn't make it a true category tag. I couldn't think of what other category to use, but didn't want the page to show no category link at all.
Category pages typically already link to their respective pages using the "Main" template, and pages are usually categorized as whatever their parent is. Like this...
Cloth is categorized as Fabric. The Fabrics page is categorized as Textiles. The Textiles page is categorized as Materials.
Perhaps the Materials page should be categorized as Resources. That would also match up the category structure. I took at look at the queries on the Resources page and don't see that it'd break anything, so I'll go ahead and make that change.