The Great Jomantai Stone—a boulder in the shape of an egg. Dimensions of the boulder: height: 2.58 cm, length: 4.7 cm, width: 3.91 cm. The largest horizontal circumference of the boulder is about 13 m. The rock that forms the colourful-gray boulder is migmatite. The Great Jomantai Stone can be seen on the Jomantai Forest Cognitive Trail.