Richard Gibson: You’ve Got Gypsum!
From the first chapter of What Things are Made Of by Richard Gibson:
You’ve got gypsum!
Virtually every home in America contains a great volume of one mineral: gypsum, the primary constituent of wallboard.
Gypsum (chemically, calcium sulfate) crystallizes from supersaturated sea or lake water when the water evaporates, much like common salt precipitates from such water. In the United States, Oklahoma is the leading producer of gypsum—nearly 3,500,000 tons of it, worth more than $26 million in 2007….
