Actually, it is exquisitely shattered glass.
My husband conscientiously decided to trim the ivy tendrils on the back patio. The gas powered weed whacker that he is so enamoured of must have caught a small pebble. In a nanosecond, our five foot thermal paned Pella window panel in the kitchen looked like this.
It is perfect for the holiday season and it happens to be breathtakingly beautiful.