Henry Pope has free clay and silica for anyone who wants it. Asheville area:
700 # of Ellen Buff, free, no charge, but you have to pick up/load. Ellen Buff is rated by Hi H2O cone 4-6. Maybe but I've fired the clay to 9 1/2 in heavy reduction. No problem. The clay is dry, dry, dry but easy to slake down.
Also I have some fine silica, 325 mesh or thereabouts (395?). Good for porcelain glazes. This is also free.
And last but not least, I have some grog that is probably kyanite, not sure. But it's grog alright. Can't be too fussy. It's free to any one strong enough to tote it.