1930's Glass and Rhinestones Brooch

I  found this beautiful and incredibly huge brooch at an antique market in Provence, in the little town of Mane this summer.
It comes with a story, the brooch belonged to the mother of the person I bought it from. It had been a wedding gift given by an uncle who was a jeweler, when she got married in the 1930's. It is unique since it was made especially for her by her uncle.