Thank you for viewing. My grandmother has been making these as a hobby for 30 years. I am helping her with the cleanup. The block pearls were purchased from a shop that sells certified natural stones. However, there are no certificates, so please consider this if you are interested. You can, of course, use them as necklaces as they are, or you can take them apart and use only the stones. There are a surprising number of accessories made with various natural stones, so I will be listing them gradually from now on. Thank you for your interest.