This birthstone pendant is handcrafted from 14K/20 gold filled wire and a simulated aquamarine standing in for the March Birthstone - Aquamarine. This stone is a pretty, more opaque, light blue and reminds me of the color of natural aquamarine. If you prefer the color and clarity of the heat treated aquamarine, I also do these in lab Spinel. 14K/20 gold filled wire is basically a tube of 14K gold with a jeweler’s wire down the center for flexibility. It wears well, does not tarnish, and has the same allergy reactions (or non-reactions) as 14K gold. Each of my birthstone pendants are handmade one-at-a-time, so although they are all similar, they are not identical. You are selecting the actual one you will be receiving. The chain is not included, but I do have a selection of chains if you need one. approximately 1/2" x 1 1/4" 14mm x 32mm 3mm bail