It’s a fascinating fabric, and it really is made of two layers of gauze. They’re woven together on the loom, which is what that white dot on the fabric is–the inside layer of gauze is white, and when the threads trade places on the loom, a little “stitch” of white shows on the purple side while a “stitch” of purple shows on the white side. You could use either side of the fabric as the right side, since the two sides are identical but opposite.
Double gauze can be quite drapey, so it’s better suited to some styles than others. I was pleasantly surprised to see it used very effectively in this adorable Birthday Party dress on the Oliver + S Flickr group. This particular version uses a Heather Ross print. Printing gives the double gauze a stiffer hand, which certainly helps to keep this dress looking crisp and summery.
If you haven’t tried this fabric yet, I strongly recommend it. It’s perfect for those really warm days of summer, which I hear are on their way.