Big and shimmery, this blacklip shell gogo makes a lovely light weight shawl pin. Averaging 60mm (2 1/4 inches) in diameter, with a 30mm (1 1/8 inch) hole, there's plenty of irridescence.
Please remember that shell is tough but brittle. If you try to bend it, it is going to break! Simply push your fabric up through the generous hole and put the stick through the weave, instead of trying to run the stick down into the fabric and back up. With simple care your shell will last many years.