Bracelets are all adjustable in length and secure with a sliding knot, or double sliding knot closure, see below for more details. String material is Green Nylon cord. Gemstone is Green Aventurine which is a variety of Quartz. Style 1. This bracelet features Green Aventurine 8mm gemstones along with some silver glass seed beads, and plastic green Evil eye beads, it is Secured with double sliding knots. Style 2. A plastic green evil eye bead at the center and silver glass seed beads. Closure is a sliding knot. Style 3. A macrame knotted pattern with silver glass seed beads and a sliding knot closure.