Fritz Heckert(?) Frosted Blue to Clear Vase with Egyptian-style Copper Overlay

This Fritz Heckert vase is quite different from what people typically think of as Heckert (usually pieces with fine enameling, or iridescent pieces like Changeant). The glass is a beautiful frosted deep blue that fades to clear towards the base, and has a copper overlay. The copper is quite thick and hand cut in what I believe is either an Egyptian-style sphinx or winged pharaoh (thanks Penny!). In some other examples I have seen I can see more of a lion's face, so I am not quite sure which, but I can clearly see a face and wings. Interestingly, I have seen this vase with the same color and overlay pattern but with a brass rather than copper overlay. I prefer the copper and its lovely patina. It stands 6-1/2" (16.5cm) tall; I believe this vase dates to about 1900.

Edited to add: Even though an almost identical vase is shown and identified as being an Otto Thamm design for Fritz Heckert in Stefania Zelasko's book 'Fritz Heckert Kunstglas Industrie 1866-1923', I have received feedback from several well regarded collectors that they do not believe this vase is a Heckert piece. After doing considerable searches I have been unable to find hardly any other Heckert pieces with copper overlays, or in this shape and decor, so I am changing the Heckert designation to a question mark for now.