gypsum - unusual sand selenite from a dry lake near Ica, Ica Province, southern Peru - hand specimen so it is not as

so it is not as easily swept out to sea by wave action

They are often derived from clays and muds and shales and fit into a metamorphic sequence of slate

In pegmatites it forms large masses and it makes up some limestones almost entirely

and various shades of yellow

Peru and the Alps were the only sources of pink fluorite at astronomical prices

gypsum - unusual sand selenite from a dry lake near Ica, Ica Province, southern Peru - hand specimen so it is not asSelenite 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 Peruvian examples were recently discovered and