February 13th, 2010

Iyo blue stone (called Iyo Aoishi in Japanese) is one of most sought-after garden stones in Japan. It is no longer harvested from the river beds in the Iyo region—the best specimens we have today in Japan are already placed in gardens (the most famous Iyo stone open to public view is in a Tokyo garden). Iyo stone belongs to the Chlorite group of minerals and is known for its distinctive white stripes in the light-blue body, which turns into dark, deep blue once wet.

David M Cobb

Iyo blue stone originates from Ehime Prefecture, on the western corner of Shikoku Island, however there are other blue garden stones in other parts of Japan. Japanese gardeners name each stone based on the region of its origin: Iyo stone, Awa-ishi, Tanba, etc. There are over one hundred such regional stone types that are favored for gardens.

The Portland Japanese Garden’s Flat Garden features one exceptionally large Iyo stone, flanked to the front and left by two smaller Iyo stones. The arrangement commemorates Philip Englehart, the first President of the Japanese Garden Society of Oregon.