Sexually transmitted diseases (STDs) remain a major public health challenge in the U.S., especially among women, who. disproportionately bear the long-term consequences of STDs. For example, each year untreated STDs cause infertility in.
Chemically known as âcalcium sulfate dihydrate,â gypsum contains calcium, sulfur bound to oxygen, and water. Gypsum is an abundant mineral and takes forms including alabasterâa material used in decoration and construction as far back as ancient Egypt.hemically known as âcalcium sulfate dihydrate,â gypsum contains calcium, sulfur bound to oxygen, and water. Gypsum is an abundant mineral and takes forms including alabasterâa material used in decoration and construction as far back as ancient Egypt.
Most gypsum occurs in its massive form, as layers of rock that often intercalate layers of shale, limestone, or dolostone. Alabaster is a common name used for particularly pure deposits of massive gypsum. Gypsum also occurs in crystal form, with the two most common varieties being large clear crystals that are often termed selenite, and fibrous crystals, known as satin spar. âSeleniteâ is the Greek word for moon, and refers to the crystals well-developed pearl-like luster that can reflect a soft moon-like glow.