New vintage tortoiseshell horn bone acrylic bracelet (blk w faint grey stripes)

New vintage tortoiseshell horn bone acrylic bracelet (black with faint grey stripes) Rare find! I’m not sure what they are made of: lightweight, warm to touch, smooth, glossy but matte texture, opaque-translucent. I’m leaning towards acrylic. Despite the material, it has a very natural and organic appeal. They look like horn or bone or faux tortoiseshell in parts especially when held to the light. Tiny nails pin the links and clasps to the components. New vintage c. 1970s. Silvertone metal fold over clasps and rings. (Not precious silver). Probably acrylic. 2.5” diameter, 22 mm wide x +1 mm thick Group photos show the variety in the collection