The yellow substance was gypsum, or calcium sulfate dehydrate, a common component of plaster.
这种黄色的物质叫做脱水硫化钙，通常是石膏的一种组成部分。
2
At the Borup Pass spring, hydrogen sulfide gas in the water is converted to stable deposits of either elemental sulfur, the most common material in the deposit, or gypsum.
波鲁普峡湾泉水中的氢化硫转化为稳定的沉积物。或为单质硫——这是沉积物中最普通的成分，或为石膏。
3
High rates of evaporation deposit thick layers of salt minerals, such as common table salt and gypsum (a chalky mineral that is a major component of wallboard).