This is a little experiment on recycled limestone paper (also known as stone paper).
The paper is super smooth and has a lovely feel to it, but it is basically calcium carbonate (80%) bonded with bio-polyethylene resin (20%).
It is water proof and resistant to tear, but is sensitive to UV which means it biodegrades when exposed to light, so it is not exactly archival material for art.
Writing on it is like writing on plastic, or plastic-coated material. It has a bit of teeth so ink or pigment grips to it but avoid pressure as it digs into the polyethylene and impedes movement.
The best part of it is that it is very resistant to bleed-through and feathering despite its thinness. Regardless of how thin the paper is, it is still stone and a small notebook of limestone paper has quite a bit of weight to it (which gives it a substantial feel or heftiness, and feels great bound in hardcover).
I personally love its tactile qualities and only wish it were more archival.
Strange Forms & Fancy 