Vintage Art Nouveau amber citrine glass butterfly powder compact or powder box by Rene Robert for Lalique

Rare Art Nouveau amber citrine glass butterfly powder compact Rene Robert for Lalique
This is an extremely rare vintage Art Nouveau powder compact by Rene Robert with a beautiful inlaid amber citrine glass plaque featuring 2 butterflies and flowers. The glass is in excellent condition with no chips or cracks at all. 
The compact body is brass with floral relief decoration around the circumference and engine turned detail on the reverse. The inside looks to be gold lined. Again, no signs of damage with the expected pattenation to the metal.
The mirror is in perfect condition which is unusual. A stunning powder compact. From research of similar items, this is by Rene Robert who worked for Lalique, although it is not signed.
The compact measures 65mm or 2.55 inches in diameter and 21mm or 13/16th inch in height.