Iridescent Shell fragment vintage bangle bracelet

Totally beautiful unusual vintage bangle bracelet, I’m not sure exactly what the inner material is, it looks like a mosaic of iridescent shell fragments cornered with a plastic coating. It has changing colors of blue, turquoise,lavender, grey and pink. There are triangles set into the domed bangle bracelet. Measures 3.25” across on the outside, 2.5” on the inside, and is 1.25” high, very nice vintage condition, no apparent flaws but check the photos for full details.