Tourmaline Birthstone for October 925 Sterling Silver Handmade Classy to go with a formal outfit -- This collar pin is made with a beautiful green tourmaline cut in pineapple cut. The collar pin features an oval-shaped sterling silver plat that makes the tourmaline glow beautifully. Tourmaline collar pin is vet classy and will take your outfit from formal wear to the next level and have sterling silver clutch backs.