Tibetan dZi and other Himalayan Beads

Above: Natural Chalcedony from the Gobi Desert. Similar lighter coloured
material would have been used in ancient times to create dZi beads.

 In the short biography* of Kyala Khenpo Chechok Thondrup it mentions the following:

"Throughout his life, he did many short retreats or less strict retreats of a month or two on enjoying the essence (bChud Len, rasayana), sustaining himself solely with the elixir drawn from flowers and a white stone called Chongzhi (Chong dZi)."

*from Masters of Meditation and Miracles by Tulku Thondup