Corundum - Var. "Ruby" -Analysis of long-wave ultraviolet lighting-

I am including some of my studies and analysis of the Corundum variety Ruby under ultraviolet lighting. This is a method usually used to distinguish heat treatments in Rubies. I think it's fascinating in every aspect. Capturing photos of UV wave lengths with an ordinary camera is not an easy task. With a simple trick, I was able to clearly show the fluorescence displayed under long-wave UV lighting.

To achieve the fluorescence shown in the photos, I use an ultraviolet light that produces a wavelength of 380 nanometers or "nm" for short. This is the electromagnetic spectrum of ultraviolet radiation. This section of wavelength is known as "UVA" and ranges from 400nm-315nm. I am currently experimenting with UV light-emitting diodes (L.E.D.'s).

 

Along with photos of Rubies under UV light, there are also photos of Ruby & Star Ruby specimens from North Carolina and even some Tennessee specimens. Corundum occurs in nearly every county in western North Carolina and even in some areas in eastern Tennessee; many of which display asterism. These specimens range in color from colorless/grey/blue to pink and purple tones.

 

                                                   Star Ruby

Among the Ruby varieties of Corundum found in the Appalachians; Star Rubies are also found in isolated localities. Star Rubies display an optical phenomenon called "Asterism" which reflects the shape of a star when the gem is cut into a cabochon instead of being facted. The star effect is caused by inclusions of Rutile (titanium dioxide) and is reflected back in the shape of 4, 6, & 12 pointed stars.