Hello all,
Many misinformed people think that only pre 1914 glass will turn purple. This is simply not true. It IS true that the supply of manganese (which causes the purple color when exposed to UV or radiation) was shut off because of WWI, but that does not mean that ALL purple or SCA glass predates 1914.
Here is an example of a 1970s vintage jar that has turned purple, probably by using a purpling box at some time, judging by the shade of purple it is.
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=6265602909
I know this is a 70's vintage (1977 to be more precise) jar because I emailed the seller and asked him to tell me the letter and number in the thread area which identifies where and when this jar was produced. I think it is very unusual to see a modern jar that has turned purple, but proves that glass does not HAVE to be old to do so.
Bob Clay
Many misinformed people think that only pre 1914 glass will turn purple. This is simply not true. It IS true that the supply of manganese (which causes the purple color when exposed to UV or radiation) was shut off because of WWI, but that does not mean that ALL purple or SCA glass predates 1914.
Here is an example of a 1970s vintage jar that has turned purple, probably by using a purpling box at some time, judging by the shade of purple it is.
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=6265602909
I know this is a 70's vintage (1977 to be more precise) jar because I emailed the seller and asked him to tell me the letter and number in the thread area which identifies where and when this jar was produced. I think it is very unusual to see a modern jar that has turned purple, but proves that glass does not HAVE to be old to do so.
Bob Clay
] .
