Update (January 10, 2012)
Dr. Joel E. Arem, PhD, FGA has completed a new research paper entitled “Obervations On The Occurrence Of Plagioclase Feldspars (PDF)“; please read this scientifically sound report and make your own conclusions.
As a group, feldspars are the most abundant minerals on planet Earth. Yet despite mineralogical superabundance and gargantuan crystal size, transparent feldspar gems (with a few notable exceptions) are usually tiny and extremely rare. The vast majority of ornamental feldspars are opaque or translucent, white, gray or a very pale hue, and often display a “phenomenon”, such as iridescence or some other type of color effect. These materials, including moonstone and sunstone, have been prized as gems for centuries. Several, including labradorite and amazonite, are widely used in jewelry.
Question: what has prevented the gemstone world from paying as much attention to feldspars as they deserve?
Answer: Extreme rarity, small size, and lack of bright coloration has prevented the gemstone world from paying as much attention to feldspars as the group deserves.
The following article is an attempt to correct this mistake and reveal the amazing story of a group of gems that may turn out to be major players in the future of the jewelry trade.
Dr. Joel E. Arem’s former article “Gem Feldspars And Feldspar Treatments (PDF)”