It's correctly Vitis vinifera 'Purpurea' and clone(s) found at local outlets in latter years really aren't as purple as it seems they should be. One I have grown for awhile here in Island County is basically green with a purple tinge by this time of the year; it is not yet in its autumn dress, which I do not remember as being stunning - but we shall soon see, I expect.

The one that is grown for spectacular fall color is V. coignetiae. The common name glory vine I take to be a reference to this feature. But it is not considered a source of appealing fruit.

The old wooden lath houses at the Seattle arboretum used to have both of these growing near one another, near the southwest corner. I don't remember what the current situation is.