This is in reply to Gerry's post in the rare white turquoise thread.
The book HANDBOOK OF GEM IDENTIFICATION by Richard T. Liddicoat,
jr., 11th Edition page 237 under the category of Corundum, lst
paragraph, 4th line, I quote the following:
"Ruby includes only the medium to dark tones of red to
violetish-red. All other colors including purple, violet, and light
red are properly called sapphire."