Garnet not like sapphire blue in subdued daylight but more reminiscent of the grayish blues and greenish blues sometimes seen in spinel. However, in white LED light, the color is equal to the best cornflower blue sapphire, or D block tanzanite; this is due to the blue garnet's ability to absorb the yellow component of the emitted light. Pyrope is an indicator mineral for high-pressure rocks. The garnets from mantle-derived rocks, peridotites, and eclogites commonly contain a pyrope variety. Spessartine or spessartite is manganese aluminium garnet, MnAl(SiO). Its name is derived from Spessart in Bavaria. It occurs most often in granite
Gemstone File Originally distributed in 1975 by hand and mail in photocopy form, the Gemstone File has appeared in slightly revised form in Hustler magazine and on the Internet. Roberts, known only to Stephanie Caruana and conspiracy theorist Mae Brussell, purportedly began gathering information in the file when Howard Hughes stole his invention for processing synthetic rubies, hence the title "Gemstone". According to Gerald Carroll, Roberts was born in New York State on October 27, 1919 and died of lung cancer in San Francisco on July 16, 1976. "Factsheet Five" publisher Mike Gunderloy collected and distributed several versions of the Gemstone File.