Assertion: gypsum | /r/HasProperty | calcined
Facets:
Source sentences:
text: It has been generally believed that most, if not all, of these imperfections are attributable to the fact that the synthetic gypsum contains minor quantities of acidic materials, which may be present as free acids, or which may be occluded within the gypsum crystals, or otherwise bound therein, which acids are released when the gypsum is calcined, thus being present as free acids in the calcined product.