Marcasite jewels are any jewel made of fragile and colored metallic stone called pyrite. Pyrite is a gem very similar to gold, but it can also be darker and more metallic than marcasite. When small pieces are inserted into silver jewelry, the Marcasite style is created. Today in the world of stylish jewelry, marcasite jewelry is widely regarded as one of the favorite types of jewelry for its beautiful and intricate designs.
Original Source: https://www.pandkjewelry.com/blog/top-5-ways-to-clean-your-marcasite-jewelry/