Fossil coral is a natural gemstone that is created when prehistoric coral is gradually replaced with agate. Corals are marine animals and it is their skeletons that are fossilized and preserved. ... Fossil coral is also much harder than precious coral.
According to metaphysical beliefs, fossil coral is a grounding stone good for bringing about change. Agate is thought to be able to help heal pancreatic disorders and improve blood and air circulation. Fossil coral is used for healing eye, skin and stomach illnesses.