All forms of Calcium Sulfate are water soluble.

• The 2003-2004 CRC Handbook of Chemistry and Physics reports the solubility of these minerals.
  
• The solubility of Calcium Sulfate (anhydrite) and the solubility of Calcium Sulfate dihydrate (gypsum) are 0.205 grams per 100 cubic centimeters.
  
• This is equivalent to about 23.8 milliequivalents per liter for Calcium Sulfate dihydrate (gypsum) and about 30.1 milliequivalents per liter for Calcium Sulfate (anhydrite).
  
• Even though Calcium Sulfate (anhydrite) and Calcium Sulfate dihydrate (gypsum) have the same solubility,
  Calcium Sulfate (anhydrite) contains 26.5% more calcium sulfate than Calcium Sulfate dihydrate (gypsum).

Garn A Wallace, Ph.D.
Executive Director / Wallace Laboratories
El Segundo, CA 12/05/2003