Hi Scott,
I accidentally jumped onto this thread just by doing a google search with "lavendar milkglass". I can attest that beyond a shadow of a doubt that authentic lavendar (or medium-purple) milkglass was occasionally made at least as early as the 1880s. Several years ago there was a project in the downtown Louisville, KY area in which excavation was done, alot of digging and moving of earth in preparation for a new waterfront park project. During this excavation the blulldozers uncovered lots of trash....construction debris, broken bricks, broken bottles, lots of glassware and pottery shards, etc, and among the odds and ends I saved a small number of shards of EAPG of various colors (my "study collection") . All dated generally from the 1880s perhaps into the early 1890s. Evidently the area once served as a casual dumping ground, at least for a period of time. Among the collection of shards is a broken base portion of lavendar milkglass, which I guess belonged to a bottle, cruet, jar, vase or shaker of some sort. The base is round, has a pontil mark and is about 2 and 3/4ths inches in diameter. The color is almost identical to the picture you attached to your message. I am positive it is from the 1880s as there were various shards from typical colored 1880s American Pattern Glass like Thousand Eye, Flower and Panel, Daisy & Button, Wooden Pail, Three Panel, Queen, Barred Forget-me-Not and others, among the assemblage. And of course this would have had nothing to do with later alteration by sunlight or any chemical / irradiation process......it had been buried for over a century. I have seldom, or never, seen this exact color in any item while browsing the antique malls, so I have been intrigued by it as well. David_W