Christine, my blacklight isn't working that well, but unfortunately no I don't think it is uranium glass - it does look like it should be though even in daylight.
I also am pretty sure as you say, that this was designed as a lamp shade. It would just practically fall over as a bowl as the base is only the size of the fitter rim, about as big as a large pontil mark, and the frilled edges would overbalance it.
The crimp is lovely, presumably done with a gadget of some sort?
Do you have pics of the triangular bowl, or was it on the gmb somewhere? I feel this is possibly Bohemian, but the bulge ribs make me think of Kralik pieces, yet the overshot, graduated colour and frills make me think Harrach (because it reminds me of that bowl). Bit of a mystifier this one.
m