I cast these nicely textured cabochons using molds that I created from real sea urchins.
You get 3 in a purple multi-toned color. The large measures 1 1/8 in diameter (30 mm) and the 2 smaller measure 3/4 in diameter (20 mm).

Use these in beadwork such as in the example or in wirework, for scrapbooking etc. Easily drill holes to turn them into pendants.

For the beaded necklace in the example photo I used one of my sea urchin cabochons.