Reply To: Chemical notation for Gypsum Home › Forums › Nemeth Code for Math and Science › Chemical notation for Gypsum › Reply To: Chemical notation for Gypsum July 27, 2011 at 1:16 pm #20997 Chris ClemensKeymaster Please refer to page 71 of Braille Code for Chemical Notation 1997, Section 4.5.1 Miscellaneous Symbols. The chemical period is explained, followed by its use in Example 4.5.1-1. Betty