All what you need is:
- stones
- acrylic paint and brushes
- little pot
- wire metal card holder
- some air drying clay or plaster
First paint the stones white, and if it's dried you can paint anything on, what you want.
If you use plaster, mix it as it written by, and place the stone and the holder into the pot. Hold them somehow as it dries.
now just paint the white parts, and you have a unique card or photo holder. Enjoy!