The first charm humans wore as jewellery, hundreds of thousands of years ago, was likely a rock with a natural hole in it.  It would have to be hard and durable to last 4 seasons.  This first decorative motif symbolized the earth or rock.  Since then craftsmen or the more dexterous of the tribe would be able to fashion whatever was requested. 

The chain that is included with most pendants and pictured with some, is an 18 inch rolo style chain 2mm wide and is Sterling Silver.  Gold chains suitable for Bellchamber Pendants are $125, because they need to be sturdy enough yet elegant.