Stone paper - who knew
"I have purchased 3 of these notebooks because I love the feel of the paper and how smoothly you can write on them. I agree with the other reviewer when it comes to using gel pens/roller ball ink and how it bleeds unless completely dry (which can take a while). However, I found using a ball point pen works great, and you don’t have to press down much to have the ink transfer to the page. I have not tried pencils, but may search out Karst’s brand instead. Overall I would recommend them, and the only reason for the 4 stars is due to the limitations of the writing instruments."