The test is most useful for emerald, ruby, sapphire, tourmaline, kunzite and alexandrite, all of which show marked dichroism.
"A Text-Book of Precious Stones for Jewelers and the Gem-Loving Public" by Frank Bertram Wade
A remarkable dichroic variety of chrysoberyl is known as alexandrite (q.v.).
"Encyclopaedia Britannica, 11th Edition, Volume 6, Slice 3" by Various
Occasional alexandrites, so called in honor of the Russian Czar, are found in the island.
"The Pearl of India" by Maturin M. Ballou
For an example of a remarkable change of this character, see ALEXANDRITE.
"Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 5" by Various