To get you started, try this combination: metallic gold, interference red, interference copper, interference blue.
Roll out a sheet of translucent on the #5 or #6 setting (fairly thin)of the pasta machine. Cut the sheet into 3-inch squares. You will need at least ten squares. More is even better.
Set half of the squares aside.
With the other half, tint each square a different color using just a tiny amount of colored opaque clay. Roll back into a 3-inch square. Set these tinted squares aside.
You should have a few pieces of scrap translucent clay left from cutting out your squares. Roll these scraps into four or five small balls and set aside.
Lay out the untinted squares on your work surface. Using your metallic and interference paints, paint each square a different color, repeating if necessary if you have more squares than colors. Let the paint dry completely.
When the paint is dry, stack the sheets starting with a painted sheet, then a tinted translucent sheet. Repeat this until you have used all of your sheets.
End your stack with one of the tinted sheets. Roll over the stack with an acrylic roller or brayer to make certain the sheets are snuggly together and that there is no air caught between the layers.
Turn the stack of squares over. Take the small balls of clay that you rolled out and make a point on one end of each of them. Press the pointed end of a ball into the surface of the stack. Do the same with the rest of the balls.
Stagger the balls across the surface of the stack so that there is a little space between each ball. Turn the stack over again so that it is resting on the balls.
Begin to press down against the top of the stack between the balls so that you have what looks like a lot of little rounded hills with gullies between them. Press the stack tightly against the work surface.
Let sit for fifteen or twenty minutes. This lets the clay cool and firm up, so it will be easier to slice.
Use a fresh, sharp blade to take thin slices across the top of the “hills” on the stack. Keep your blade parallel to the stack of sheets. This takes a bit of practice, but once you get the hang of it, it will be easy.
Turn your slices over and lay them onto a sheet of waxed paper. Choose the sides that look the most colorful and shows the metallic sheen or iridescence best.
Lay your slices onto the surface of base beads (preferably made with translucent clay,) or onto any other base shape that you want. Bake at the temperature recommended by the manufacturer of the clay you are using.
Remove the items from the oven when done and while still very hot, drop them into ice water. Let cool.
Sand the items in water with a #320, #400, and #600 grit wet/dry sandpaper. Buff to a high shine. You will see the depth appear and a wonderful iridescence emerge.
This is a great technique to use for experimenting with color and types of paint. Don’t be timid with it. Try anything that comes to mind. You never know what you may come up with.