Factsheet on: What is Gypsum?
Gypsum, but is comparatively limited in its technical applications. The content of Gypsum in sedimentary rock varies from 75% to 95%, the rest being clay and chalk. B. Extracting Natural Gypsum Gypsum/Anhydrite are produced from opencast mines, or underground mines using pillar and stall mining methods, that give extraction rates of up to 75%.