I purchased this at a gemstone and natural stone shop. It's a real stone. I've forgotten what kind of stone it is, but judging by the pattern, I think it might be something like tiger's eye. It alternates between a stone that shines blue like tiger's eye and black stones. The inner diameter is about 6-6.5cm, but it seems like it can be stretched to about 20cm. The elastic is a strong one made of many thin strands bundled together. The stones are about 1cm in size. AI Description: Stylish bracelet using black and blue natural stone beads. - Color: Black and blue beads - Material: Natural stone and silver beads - Design: Beaded bracelet - Features: With silver metal parts Thank you for viewing.