Beautiful old piece. Estate sale find. High content of magnesium in the glass of this lamp allows it to glow under black light. Has manufacturing defects and bubbles in the glass which also proves its age. It does have a surface crack at the neck which has not affected its use. This can be seen up close in the last picture. The Magnesium content of the glass causes the glow under black light.Magnesium was used to clarify the color of clear glass from about 1860 through 1915. The resulting glow under black-light helps to date the lamp and also makes for great Halloween decor. Please look at pictures for more details. We will package securely and ship promptly!