Red Glass Mystery

[ska69]

I have been excavating a privy in my back yard for several months and yesterday I discovered my first two pieces of red glass. Judging by the other glass and pottery I have found at the same level, I believe that these pieces are circa the 1800s. When I located the pieces in the soil they were a deep ruby red color, however, once I removed them and allowed them to sit in the fresh air for a few minutes, the edges turned an icy white color that does not wash off with water. I understand that old glass from this era can change color over time from sunlight, etc. but I have never seen glass change color this rapidly. Does anyone have any info on this phenomenon that may help me in identifying these pieces?

 

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[wainzoid]

Im not sure about your piece of glass. I do know that some old fruit jars that were originally clear, may turn purple when exposed to the sun for a period of time. This is caused by chemicals or impurities in the glass. Manganese I believe is what turns purple. People see these fruit jars with the purple tint and think they found a special jar or bottle, but in fact it is just a common clear one.

 

[pippinwhitepaws]

nitrate from the contents of the privy?