<prompt> True about x-ray diffraction data for set gypsum products:There is less than 50 dihydrate present in type 4 stonesThere is less than 40 dihydrate present in type 2 die materialsThere is less than 30 dihydrate present in type 1 plasterThere is less than 20 dihydrate present in type 5 stones  <response>: The setting reaction takes time to complete and changes in the mixture begin as soon as the hemihydrate and water are mixed together. X-ray diffraction data for set gypsum products indicate that there is less than 50 dihydrate present in Type IV and V stones, about 60 in Type II die materials, and over 90 in Type I plasters.Phillips Science of Dental Materials ed 12 pg 184 