Unsigned huge blue glass brooch

A big blue rock with style and glitz and grace not to mention quality of construction. This magnificent pin is claw set in a sturdy framework of brushed silvertone. The quasi triangular art glass stone that is the focus of this piece. Measures approximately 1 1/2 inches x 1 1/8 inches and is flanked on either side by elongated navette rhinestones of montana blue and olivine. On top are two smaller olivine navettes and a startlingly crest of eisenberg style crystal ribbons, and medium sized capri blue chatons pop up here and there to fill in any needless blank spaces. This has got to be one of the finest costume brooches from the juliana era mid to late 1960s ever made and I have not a clue whodunnit. It measures 2 3/4 inches across and 2 inches from top to bottom and is in mint condition. unsigned.