Abalone shell from Mexico - Smudging bowl

Our Abalone shell is polished and is showing a rainbow of colors and the outside is natural.
Although there is a dark spot in the middle where the mollusk was attached.
Also, some of the shells may be a rough / chipped around the edges. The outside part of the shell has a crusty cortex.
Various shells pictured to show as examples of the different chips in the edges and dark spot in center of shell.

The ceremonial smudge bowl is used as a receptacle for burning smudge sticks such as sweetgrass, sage, incense and cones.