What does gfm on a gold chain?

"GFM" on a gold chain typically stands for "Gold Filled Metal." This indicates that the chain is not solid gold but rather has a layer of gold bonded to a base metal. Gold-filled jewelry is more durable and affordable than solid gold while still offering a similar appearance. It's important to note that gold-filled items can tarnish over time, but they generally maintain their quality better than gold-plated items.