Early 1900s Clear Manganese Glass Jesus Crucifix Candle Holder

While many of us already know about uranium glass, there is a lesser known UV reactive glass called manganese glass.  You may find many glass pieces from the 1950s and before containing manganese, particularly clear glass.  But why?  Manganese dioxide was often added to the glass making process to achieve clearer glass.  Iron is a common impurity in the glass making materials causing a greenish tint, the manganese dioxide reacts with the iron causing the greenish hue to turn more pink.  The result is a much more clear glass.  You will also find in large quantity, manganese dioxide will turn glass purple which was another common practice pre-1930s. Manganese is a little different than uranium glass in that it takes a different wavelength to glow.  Be sure to use a 365nm black light to see the full effect of the manganese in the glass. Manganese glass, while still available today, became less popular after the 1950s because of the toxicity and health effects.   This crucifix candle holde