Colorful Seahorse And Round Half Drilled Beads

I don't know much about these beads. I got them in a jar of vintage jewelry. I think they are acrylic, but I'm not sure. They aren't the cheap plastic. They look nice. Please see pics. I don't know what millimeter they are, so look at tape measure. Pet friendly home. seahorse beads jewelry making earrings necklace bracelet half drilled acrylic