The flowing petals of this Art Nouveau period sterling brooch make me think this is an Iris.  This beautiful pin weighs 10.9 grams and is 57mm wide.  It is in great antique condition with light surface wear and is marked as shown (please note the back section and pin are not sterling and the piece is hollow.  This is a typical manufacturing style of this type of brooch from early 1900s.  Follow me on Instagram for special deals ;) @mindilynjewelry