Yusuri is a shrub that lives on the seabed. It is a living organism and over time, its surface gets smooth, the hard shell is detached and only the "body" of the bead remains.
If you look carefully after removing the shell from the surface, reddish hues appear, a property that is found only in Yusuri. You will also notice that after use, an iodine salt scent emerges from the beads.
Sometimes we see yusuri beads decorated with various materials. This is mainly due to the Egyptians who for religious reasons would carve yusuri and place materials like silver, gold, ivory, enamel, etc on it.