Sand stone beach stone with a worn-away center hand picked from the Great Lakes is drilled with a diamond bit. The center (darker) portion totally reminds me of a worry stone. Pictures do not do this stone justice. This is a perfect pebble to take your worries away. Jump ring is sterling silver. Approximate size is 2" long by 1.25" wide. Comes with a 16" or 18" round link sterling chain or an 18" round link stainless steel chain. If you have a preference, let me know in the notes!