Garnet and Mother of Pearl EarringsGarnet forms when sedimentary rock with a high aluminum content, is under intense heat and pressure. Garnet are formed by metamorphism, the garnets start out small and grow over time, displacing and replacing the surrounding rock, commonly schist. Garnet has been used as a gemstone for thousands of years and has been found in jewelry in Egyptian burials and Ancient Rome. Almandine Garnet is the most common type of Garnet and it is often referred to as