High quality acid etching for this rare decoration.
Paul Nicolas (former decorator of Emile Gallé until 1904) used 3 layers of glass to reveal the blue of the open flowers and the mauve of the still closed buds.
The base layer ("poste") of whiteness frosted with diluted acid (Gallé process) gives a fluffy appearance.
Signature on the base of the foot: P Nicolas Nancy (in cameo).
Magnificent vase created around 1925.