Kurama Stone

Kurama stone forms a small stock that intrudes the sedimentary rocks of the Tamba belt north of Kurama-dera temple in Kyoto. Kyoto Prefecture's Red Data Book reports that it is currently quarried as garden stone at two sites, Momoi-dani and south of the old Hanase Pass. The large amount of pyrrhotite is thought to come from sulfur that the hot magma took up by reacting with the surrounding mudstones; similar small pyrrhotite-bearing bodies occur elsewhere around Kurama.

The distinctive feature is the rust color: pyrrhotite is unstable in air and readily reacts with rainwater to form iron hydroxide (limonite), giving the whole stone a reddish-brown tone. Stone from Kurama itself is also called Hon-Kurama ("true Kurama") to distinguish it from Tamba Kurama stone and Koshu Kurama stone, which are quarried in the Tamba region and Yamanashi Prefecture.

Kurama stone has long been esteemed as a high-grade stone for tea gardens and is favored by tea masters for stone basins (tsukubai), shoe-removal stones (kutsunugi-ishi), stepping stones and stone lanterns, usually keeping its natural rust-colored surface; the stone was traditionally worked at Kuramaguchi. The word Kurama-ishi already appears in an 1856 kabuki play, Kuramayama.