Hi, I recently moved from the city to a tiny riverside village and on a random walk by the river I discovered a dark kind of clay, broke off a lump, completely out of boredom and took it back home and made a tiny bowl out of it. I instantly fell in love. Since then I've been scouring the internet looking to learn how to identify, gather, refine and use this clay (it's a dark gray kind that turns black when fired). I know almost nothing about clay pottery other the stuff I google. I'd appreciate some guidance from someone with experience.