Peridotite outcrops are found in front of Power Station No. 2 run by Nippon Denko Co., Ltd. at the entrance to the Horomankyo Gorge. Although their surfaces are generally reddish brown, fractures here and there reveal the olive-green color of the mineral olivine - a major component of peridotite. Other minerals in peridotite include yellow-brown orthopyroxene, emerald-green clinopyroxene and jet-black spinel. The beautiful colors of stones in the area can be appreciated to their full extent under a loupe.