The face of the Great Yin
According to Taoist mysticism, she is
the wise initiator of spiritual seekers.
She was born together with heaven and earth,
I don't know how many years ago.
Her numinous transformations are inexhaustible.—Tao Qian
Xi Wang Mu is also known as Zhin Mu, Metal Mother, since she presides over the direction West, which is associated with the element metal, the color white, and the lungs. The tiger is the animal associated with West, and one old Han dynasty text describes her as having a leopard's tail and tiger's teeth. According to some translations of the Shan Hai Jing, she "is fond of roaring."
She roams through the Nine Heavens, which she governs. She is often shown riding on the back of a phoenix, and sometimes she rides in a chariot of purple clouds.
The gods meet at the sanctuary of Xi Wang Mu in the Kun Lun mountains. She sits on a tiger and dragon throne, surrounded by river goddesses and jade maidens.
"As for the mountain of the serpent shamans, on top of it is a person brandishing a cup as she stands facing east. One source calls it the Tortoise Mountain. The Queen Mother of the West leans on a stool; moreover, she wears a sheng and carries a staff. To the south are three blue birds who take food for the Queen Mother of the West, north of the Kun-Lun barrens." —Shan Hai Jing
(The sheng headdress of Xi Wang Mu symbolizes a weaver's spool or shuttle.) The above quote is taken from Suzanne Cahill's wonderful book, Transcendence and Divine Passion: the Queen Mother of the West in Medieval China, Stanford University Press, 1993