What the Romans did for us

My daughter, who was six at the time, found this piece of glass on a path at Vindolanda fort by Hadrian's Wall. She showed it to one of the diggers who said: "You just keep it dear." I don't think she was that botherd about it, and I've kept it ever since. (I know this smacks of sheer  paternalism.)
    I'm showing you this for two reasons. Firstly because the colour is much the same as yesterday's bottle, which I thought was interesting. Secondly because the Black Dog is visiting and I want to feel good about something.  
    This fragment is probably from a quart (2 pint) bottle with square sides and a round top. At the Vindolanda Museun, they had loads of them. On the left of the piece you can see the right angle turn. (See extra shot) I believe it's from the late Roman period, circa 300 AD