Triassic sequences in Europe, America and Africa. In the Spanish Iberian Basin, they are
associated with corrensite and gypsum, which characterize saline mudflat and salt-pond
facies. Similarly, shaped crystals occur as dolomite, quartz, chalcedony or even copper
pseudomorphs after aragonite in several parts of North and South America, and they are
currently forming in association with hydrothermal spring deposits in Kenya. In Spain, this …