Use flat/circular floral pebbles (clear glass without an iridescent glaze) Layer them with nail polishes to create images that resemble the Hubble Telescope photos of distant space. I've painted super novas, black holes, and moon images against a starry background using glitter nail polishes and layers of faintly applied colors. Use various tipped paint brushes (for acrylic paints). Clean with 100% acetone. Think in reverse when painting these images as you view the image from the top of the floral marble while you paint the image on the reverse. Start by using a layer of clear/glitter polish, then add colors. Keep a bottle of professional nail polish thinner/extender on hand. Place a drop or two of nail polish on some tin foil and then add a drop or two of nail polish thinner/extender to thin out the polish so you can paint with it. These make beautiful pendants or unique refrigerator magnets.