If the seem runs completely through the top of the bottle, that means it was machine made post 1904. For it being a purplish bottle, it was probably exposed to sunlight for a long time and the amount of manganese in the glass can do it to bottles even today. Probably worth a $1 or $2 but would take a while to sell.
Alot of clear glass prior to the onstet of WW1 had Magnesium in the glass mixture. Over time it react to sunlight(UV) and purples. This can be sped up greatly with use of a germacidle lamp, causing a bottle to be almost black/purple. One of my favorite colors of bottles. Good looking quart whiskey, should clean up and make a nice window bottle!