The Astrologer's Handbook. Frances Sakoian and Louis S. Acker. Harper and Row Publishers, New York City. 1973.
The Curious Lore of Precious Stones. George Frederick Kunz. Bell Publishing Company, New York City. 1989. Pgs. 275-306.
The Little Giant Encyclopedia of the Zodiac. The Diagram Group. Sterling Publishing Company, New York City. 1997.
Special thanks to the Rev. Mary Kisner+ and Mr. Francis Kisner of Kisner's Gems.