gypsum - sand selenite rose from a dry lake near Oujda, Morocco - hand/display specimen which support the north end

which support the north end of the Golden Gate Bridge

a name given to it in Elizabethan England from its use in Medieval Russia as a cheaper alternative to glass in windows

Fibers from the McIlroy Mine have been available as standards from NIOSH since 2014

hardness 6-6

which locally forms dunes

gypsum - sand selenite rose from a dry lake near Oujda, Morocco - hand/display specimen which support the north endSelenite 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.