I have a black glass vase about 12" high.The mouth of the vase looks like the petals of a flower....if that makes sense.
It may have been a decoration on the table at the Ball or a gift to someone in the Court. The writing on the vase states "Rex 1917" in white.

Hello Sioux,
It is in fact a flower vase around the 1920s or later. If you hold it up to a window with a bright sun you might find that instead of being black it is in reality a very deep purple.

If this vase is what I think it is hang onto it as it could be worth a buck or two.

Respectfully,

Ralph Jones