Blue lace agate is a pale blue sort of agate whose white and blue bands twist in a wavy, lace-like pattern; Wikipedia classes it, like agate, as a variety of quartz. It formed in cracks rather than in rounded nodules: at its chief source, the Ysterputs Mine in southern Namibia, worked from 1962 until 2017, it filled fractures in Jurassic dolerite, and similar material has come from Kenya, Malawi, Zambia, Georgia and Turkey. Unusually for an agate, most of its chalcedony is the length-slow kind called quartzine, and its soft blue is thought to come from light scattered by minute cavities and particles inside the stone. It is cut for jewellery, and pieces with crystal coatings are sought by collectors. Cunningham assigns it to water and has it worn or carried for peace and happiness, held in the hand to ease stress, and set among light blue candles at home to calm family quarrels. Hall presents it as a gentle, cooling healer of the throat chakra that helps people put their thoughts and feelings into words, lets spiritual truths be spoken, and brings peace of mind.