What creature are these beads from?

I know it's not very old, but is this bracelet made of operculum from shells? Or what? Each "bead" is rounded, not cut. The surfaces are not consistent. I love the colors, they are a bit darker and more pink than abalone shell, which is more green than these are.

There are 3 round beads that feel like stone, can anyone identify these also? I included a shot of my small hand, so you can see the scale.

 

I wonder if they might be Button Pearls.

 

Name I have seen is coin pearls. It's the beads in between that puzzle me. Don't think they go together very well.

For example:

https://www.ozbeads.com.au/products/peacock-black-15mm-coin-freshwater-pearls-15-5-strand

 

Bdigger, Bronwen, thank you both so very much. They are definitely coin pearls, no idea what the stone beads are though they don't go very well together in my opinion either!

I'd remove them if I could do so without having to restring the bracelet. I've never seen the button shaped pearls before, so my small purchase was inexpensive and served to educate me! Thank you both so much for this. And I've worn it too!

 

Mine are much more "pink-brown" than the South Pacific blue-green color. I wonder if they would be from the same ocean waters? I have recently seen light purple pearls come from one of my favorite natural pearl jewelers in Hawaii!

 

These coin pearls don't come from ocean waters
Dyed Chinese cultured freshwater... The creature they come from is mussel

 

OH!! Thanks for pointing out, Kyra! I missed the word "freshwater" in Bronwen's link!