Signed Handcrafted/painted Lustrous Irridescant Glass Lamp Shade

This gorgeous lamp shade is made of hand-blown/painted glass with an iridescent, shimmering finish that reflects multiple colors, referred to as favrile. The handpainted florals includes prominent pink purple blooms with soft blue-gray leaves & berries and accented with delicate gold detailing. The edge is distinctly ruffled or wavy reflecting Art Nouveau or Art Deco influences, similar to designs by Tiffany Studios or other art glass producers. The lip that attaches to the lamp measures approximately 1/2 tall. See photos for additional measurements. No damage observed, minor vintage wear. Please review all photos as they are part of the description.  This shade is signed, however I've not been able to confidently identify it yet. It could be Erwin Eisch or Poschinger or someone else entirely, however it does have many characteristics of a German glassmaker.