The Sormuskivi, located on Nuijamaa Church Hill, is one of Finland's largest colonial boulders, a reminder of the Ice Age. It is also the stone of many events and stories. The visible part of the Ring Stone measures 8 m x 8 m x 7 m, and part of the boulder is covered by earth. The boulder is composed of rapakivigranite, or more precisely viborgite, which is characterised by pale plagioclase rings surrounding rounded calcareous grains.