After eating pistachios, I noticed that their shell are very hard and rigid. So I got this idea that they might just be good for creating jewelry. So I quickly googled them out and found out that people are there are creating handmade jewelry with pistachio shell. Here are some photos I found on google.com
Beaded Pistachio Shell into a necklace. Luv it
I don't know if this is a pistachio, but I can see how it can be done.