Antique diamonds have the unique property of changing their hues in different lighting. This incredible old European cut diamond has the most range we've seen–it goes from a light yellowy green indoors, to near colorless outdoors, to a blue hue in direct sunlight! Antique diamonds were mined much closer to the surface of the earth than modern diamonds are. They were exposed to more radiation which gives them their unique color change properties. Its blue glow in sunlight occurs because of the diamond's absorption of elements boron, nitrogen, or aluminum. Under ultraviolet light, it will glow bright blue! We have EGL certified this diamond and they have graded it Q-R color grade, VS1clarity grade, and .58 in carat weight. It is set in a gorgeous, simple yet bold, square-edged 14k rose gold mounting handmade in 1883. A faint engraving on the inside of the band from its original wearer gives us the date. The band is graduated and is 4mm at its thickest point, alongside the crown-like prong-set diamond. It is currently a size 7 1/2 and may easily be resized up or down upon request.