Metamorphic rock types have formed at same time as the ancient mountain ranges of planet Earth began to gain their shape. When mountain ranges formed near the borders of tectonic plates, the baserock became folded and surrounded by high temperature and pressure. The minerals contained in the bedrock began to arrange themselves in a different way, and the old types of igneous and sedimentary rock began to form new, metamorphic rock types.

The most common type metamorphic rock found in Finland is gneiss. It has been formed from granite, which means that it contains the same minerals as the original igneous rock type. However, due to its changed structure, gneiss has more stripes than granite and is even more sturdier. 

The hardest rock type found in Finland is the metamorphic quartzite, which has been formed from sandstone. It can be found near the highest Finnish peaks, such as Koli.

Marble and mica schist are valuable types of metamorphic rock used in buildings. They have been formed from claystone and limestone, respectively.