I'll readily admit that pre-1920s glass is a complete mystery to me, but I've ended up with a mass of apparently older pieces thanks to three very big and very random joblots at the local auctionhouse today containing a mix of old English glass and some 1970s Scandinavian glass (that I was actually after).
So I thought I'd use it as an opportunity to educate myself a little.
After a bit of t'interwebbing, I've spotted a few decanters with a similar style of cutting, but they've been dated anywhere between c.1800 - c.1880. Nothing immediately leaps out of my small handful of books on older glass.
The decanters are of thick glass, mould-blown into shape rather than carved out, and very deeply-cut on the shoulder. They are star-cut to the base.
Height is about 10.5 inches / 265mm.
Any help greatly appreciated.