On Yuan Chwang's Travels in India, 629–645 A.D. v2.c19.106

v2.c19.106

Our pilgrim goes on to tell that near the Bodhi Tree, on the west side, was a large temple containing a bronze (tu-si) standing image of the Buddha adorned with precious stones. This image faced east, and in front of it was a dark-blue stone beautifully ornamented. The temple represented the Hall of the seven precious substances made by Brahmā for Buddha on his attainment of bodhi, and the stone was the seat of similar substances presented by Sakka on the same occasion. Here Buddha remained for seven days, absorbed in meditation, and lit up the Bodhi Tree with light emitted from his body. In the long lapse of time, however, the precious substances had changed into stone.