Beautiful piece Matchbox, Does this piece fluoresce under black light?? Looks as if it may have been made with Uranium Dioxide, You will need to test it under black light to see if it does fluoresce bright green under Ultra Violet light (blacklight) Looks to be Victorian era glass, hand painted and believe I can see a few bubbles within the glass ( all hard to tell from photos
)I have not seen this makers mark before and did a quick search and came up empty
. Glass can be almost impossible to track but with the mark your chances are better. I would get more info from family as to the region and surrounding towns and begin to search glass manufacturers in all surrounding areas. Also if your grandmother traveled to certain areas on special occasions. Please post any info you get as it will help myself & everyone here search.