Calcium Polysulfide degrades to Calcium Hydroxide and Sulfur.  Calcium Hydroxide is a Highly Alkaline (basic pH) solution that manipulates the ionic electrical charge of the Sulfur atom creating the negatively charged "Sulfide" ion.

 

Calcium Hydroxide is an integral component of the "Lime Cycle."  Roman Engineers learned thousands of years ago that combining slaked lime with volcanic ash produced a high strength, cementious material suitable for construction.

 

Volcanic Ash, Coal Ash and Ordinary Portland Cement are uniquely similar in their chemical composition.