This item uses natural stones. The string is made of elastic rubber. Blue-green chalcedony 8mm & 6mm / Crystal 8mm Inner diameter: Approximately 50mm 【Crystal】 Crystal has a clear and pure shine. Since ancient times, it has been known as a "stone of purification" and is considered a versatile amulet, despite its simplicity. It harmonizes well with any stone and brings balance when combined with others. ◇ Due to the use of natural stones, there may be chips, scratches, and variations in color. We hope you enjoy these natural characteristics. ◇ Please refrain from purchasing if you are looking for the perfection of a mass-produced product, as this is a handmade item. ◇ There may be cases where the knots or ends of the string are not completely hidden or are left as part of the design. ◇ The color of the actual product may differ from the photos depending on your device and environment. Each stone's unique color and pattern is one-of-a-kind. We hope you enjoy these power stones casually, like a small amulet that accompanies you in your daily life. Please check the profile for bulk purchases.