I have been painting pebbles and exploring inks and supplies.
Some of the tools and inks I used for painting and drawing these pebbles: Black Faber Castell Pitt artist pens, Staedtler 0.4 technical pen with white Staedtler ink, Royal and Langnickel Clear Choice 00 round synthetic brush with white Daler-Rowney acrylic ink or white Pergamano indelible drawing ink.
Some of my unique pebbles are available at my Etsy Shop