This is my favorite necklace, and I wear it most days. It's a small star. The mathematical shape is called a small stellated dodecahedron. The center of the shape is a dodecahedron, which is a 12 sided shape made up of pentagons. Each pentagon was extended to the point where it meets up with the other faces, and lines were drawn to those points, making up 12 stars from 12 pentagons. It shares the same vertex arrangement as a regular icosahedron. This item ships on a black cord necklace.