This is a limestone matrix with andalusite crystals. It is also called Porphory. It received the name Chinese Writing Rock or Stone because of the crystaline structure resembling the Chinese characters of the written language.
The stone is known to be found in the Auburn, California region of the foothills of the Sierra Nevadas. It strongly resembles the Chrysanthemum stone, another limestone matrix and andalusite crystal stone from China, but the crystals in that stone spray out into a chrysanthemum pattern - hence the name. This stone comes from the Yangtzi River Valley of the Hunan Province of China.
Colors range from a very dark gray or almost black to creamy white, both of which have a slight greenish cast. A dramatic looking stone, it is a 5-6 on the Mohs' scale.