The choice of N. gibbosulus in Mediterranean websites and N. kraussianus is South African sites is usually a purpose of their availability in the vicinity with the websites, but will not explain why this genus was most popular above other shells of similar dimensions and shape. A comparison in the https://medium.com/@spoilmevintagediy/the-rich-history-of-beadwork-a-journey-through-the-ages-4e4fd2e474cf