I used a number of different Unity stamps on all these coasters.
Use 4x4 distressed looking tumbled tiles (don't get the shiny ones), You can get them at Home Depot or Lowes.
Wipe the tile off.
Using any stamp that you like, stamp the image using StazOn. Let dry for a minute.
If you want to color the image (ex. butterfly) use a blending tool as pictured above or even a Q-tip would work and dab on the color so it doesn't smear. Only use StazOn inks.
Bake tiles at 350 for 10 to 15 mins. You do not have to seal them. Some people say this is not necessary, but I do bake mine.
If you're going to use them as coasters, be sure to put round felt pads on the bottom corners.
That's it!! Have fun.