Hi Mark,
At the back of each issue of Art Jewelry is a supplier reference page, called Contacts & Suppliers. It's on page 85 of the May 2007 issue featuring that Gumdrop bracelet. Looking at the copy in front of me, it says that the quartz triplets are available from Gem Crafters, Inc. and you can contact them at gemcrafters@hotmail.com
Good luck!
~Addie~