This tiny pendant or charm was purchased in Italy and is marked AR 30 on the jump ring at the top which indicates that it was created in Italy by artist 30 (shown in last photo).  It has a 750 stamped on the other side of the jump ring indicating 75% gold or 18K.  It consists of a red stone heart that appears to be carnelian in a yellow gold bezel surrounded by a rope-style border. It was purchased back in the 60s. It weighs one gram.  It is 2 cm from the top of the loop to the bottom of the heart. It is quite shiny (both the red stone and the gold).