Old School Geekery Floating Locket Kit – Includes Glass Locket (Large Size 30mm External Diameter) Necklace: 20 Inch Chain Back Plate: I Love You to the Moon and Back and Birthstones: Set of 12 (5mm Diameter) Gemstones Birthstone chart is not included, but can be found easily online. Dark Red:January Light Purple:February Lightest Blue:March Clear/Diamond:April Dark Green:May Light Pink:June Red:July Light Green:August Dark Blue:September Bright Pink:October Amber Orangeish Yellow: November Bright Blue:December LOCKET DETAILS, HOW TO BUILD USE THE KIT TO BUILD YOUR OWN LOCKET: Step 1: Twist Open Locket, spin the face of the locket off the body of the locket. Step 2: Insert Back Plate Step 3: Insert your Family Birthstones Step 4: Twist locket face back onto locket back. Step 5: Show off your beautiful family!