Very large unknown piece

I have the opportunity to purchase this piece, but am not familiar with the form or value. I am being told it is earlier and a museum curator gave an unofficial evaluation as a Navajo chest piece.
Over all size is approx 6", feels like it weighs about 5 ounces. The turquoise pieces appear to be solid, and have a few very small cracks. If anyone can help I would greatly appreciate it.