is a igneous rock

Rock (geology)

In geology, rock or stone is a naturally occurring solid aggregate of minerals and/or mineraloids.The Earth's outer solid layer, the lithosphere, is made of rock. In general rocks are of three types, namely, igneous, sedimentary, and metamorphic...

, created from lava and ash. Ōya stone was famously used in the facing of Frank Lloyd Wright

Frank Lloyd Wright

Frank Lloyd Wright was an American architect, interior designer, writer and educator, who designed more than 1,000 structures and completed 500 works. Wright believed in designing structures which were in harmony with humanity and its environment, a philosophy he called organic architecture...

's Imperial Hotel

Imperial Hotel, Tokyo

The Imperial Hotel, Tokyo, Japan, was created in the late 1880s at the request of the Japanese aristocracy to cater to the increasing number of western visitors to Japan. The hotel site is located just south of the Imperial Palace grounds, next to the previous location of the Palace moat...

 in Tokyo

Tokyo

, ; officially , is one of the 47 prefectures of Japan. Tokyo is the capital of Japan, the center of the Greater Tokyo Area, and the largest metropolitan area of Japan. It is the seat of the Japanese government and the Imperial Palace, and the home of the Japanese Imperial Family...

. One reason this stone was used is because it has a warm texture and is easily carved, which allows much versatility. Ōya stone can have different colors and is also fireproof.

Ōya stone can only be found in an area 4 kilometers to the east and west by 6 kilometers to the north and south around the town of Ōya, near Utsunomiya

Utsunomiya, Tochigi

is the capital and most populous city of Tochigi Prefecture, Japan. In October 2010 the city had an estimated population of 510,416 and a population density of 1,224.49 people per square kilometer. The total area is 416.84 km². had a population of 888,005 in the 2000 Census...

, but there are reserves of around 600 million tons.