Looks to me like 2 ring hitches attaching the pendant bit made using the 2 ends of the leather. These are then attached to the main part with 2 double overhand knots (normally these are slid together to form the Double Fisherman's aka Grapevine knot). If I'm right then this loop is adjustable but as it's leather it may take a bit of effort to slide the knots. Link below to one of many sites showing the knot - in your case tie the 2 halves - one each side of the pendant - and tighten but don't draw together. The ends may have been tucked back into the knot or cut short - difficult to tell from the photo.
Barry
http://www.animatedknots.com/doublefishermansrescue/index.php