gypsum - sand selenite rose from a dry lake near Oujda, Morocco - large hand/display specimen aragonite CaCo3

aragonite CaCo3

The brown color is unusual and is derived from iron in the limestone that was released by the metamorphism

These attractive clusters are washed

These specialized  crucibles are used in determining the mass of precipitates

concentrated into a huge dune field in present day southern Utah

gypsum - sand selenite rose from a dry lake near Oujda, Morocco - large hand/display specimen aragonite CaCo3Selenite gypsum sand rose CaSO4 2H2O Selenite gypsum sand roses form in seasonal desert lakes as they dry. Selenite is typically transparent, but when it crystallizes in sandy conditions it forms rosettes of flattened crystals, the rose petals, which are either encrusted with sand or with sand embedded throughout. The color of the gypsum crystals depends on the color of the sand in that dry lake. These Moroccan examples are particularly attractive.