I had a visit from my sister and great niece a couple months ago. Hmm, what to do after walking the beach, tide pooling and looking for agates? Paint rocks! Such a fun and easy thing to do. We got out the acrylics and coated them after with some Modge Podge (or acrylic medium). To make the smaller lines I used permanent ink pens.
NOTE: It is great fun to take them to back the beach – now painted – and leave for others to find!
Here is a couple of them.