Vintage 14K Gold Filled Pendant With Marquise Cut Black Alaskan Diamond

Unique vintage pendant made with natural Earth mined black Alaskan diamond. It is marquise cut and heavily included with black hematite. Stamped GF and has a makers mark. I believe it is either 14 karat or 12 karat gold filled. Such vintage jewelry is considered valuable and collectible as it contains quite a bit of real gold, much more than in gold plated items.