- gold filled item- Birthstone of OctoberOpal is said to be a stone for creativity, as well as bringing emotional balance and calm. This gold filled stacking ring boasts a beautiful 4mm natural Opal gemstone. Lovely worn alone or alongside my other gold filled ring designs to create a stacking set.Each item is handcrafted to order. As with all natural gemstones, play of colour may vary, especially in different lighting, although I will match the stone as closely as possible to the picture above.