A diamond refers to the existence of several alternative paths between two points in the network. This notion plays an important role in traffic engineering where it is needed, for instance, to balance the traffic load between several paths. These diamonds might be found at the AS level or the IP level. This paper is interested in the IP level and proposes a recursive labelling method for diamonds, RLPA. In this paper, we show, on a subset of skitter data, that diamonds are mainly composed of a single intermediate node, have two edges, are basically symmetrical and are located between 10 and 15 hops from the traceroute source.