This is not required information for students of EPS2

The History of Different Synthetics Used As Diamond Imitations

SYNTHETICYEAR OF INITIAL USEPEAK OF ANNUAL PRODUCTION (IN CARATS)YEAR OF PEAK
SapphireAfter 1905unknownunknown
SpinelAbout 1920unknownunknown
Rutile1948750,0001955
Strontium nitrate19551.5 million1968
YAG196840 million1972
GGG1975small1976
Cubic zirconia197660 million1980-81