Coasters for Fun and Profit
My coasters (examples pictured below) are made of stained glass, mirror, and a smooth dense concrete. They are all approximately 4" x 4", have a cork back, and are sealed for stain resistance.
In 2003, I published a guide to making coasters and updated it in 2011. In the book, you will find detailed instructions for making coasters my way as well as tips and tricks to getting it right as well as 42 of my favorite patterns.
The full e-book is available for purchase as a .pdf file on this site, or as a paper copy mailed to you.