I purchased this water bottle in 2009 from another collector and it is etched Blenko 2009 on the bottom. In 2009, there was no purple color in the catalog list of colors, so I referred to this as purple experimental. Last year on my annual visit to Blenko, I found out that every so often Blenko does a run of Violet glass and makes lamp pieces for a lamp manufacturer. They were doing this at the time of my visit. So, I now believe that they were also doing so in 2009 and a few Violet water bottles were made at that time. If you see a purple water bottle with the 2009 date on it, grab it! They are few in number.