Where can I buy seal cutting stones in Beijing?

The streets and alleys of Liulichang are selling calligraphy and painting supplies and books. There are Rong Baozhai, China Bookstore, Yidege Ink Factory and Ancient Books Bookstore. There are a lot of Four Treasures of the Study and seal cutting materials in it, which are very complete. Prices are high and low. You can take the subway to the exit of Quanjude Roast Duck Restaurant. Walk in. See the school gate of the middle school attached to Beijing Normal University and go on.