That is a lovely gift from a wonderful friend, and I’m sure you will always cherish it.
If I had to make a guess I would think that the turquoise might be from the Kingman mine, but that is always just an educated guess without verification from the source. I can’t tell if it’s natural turquoise or stabilized, but either way it’s very pretty. Your friend’s time frame fits in with what I would have guessed for the age of the squash. I also suspect it’s sterling silver. But I am not an expert; just someone who has loved and collected Native American jewelry for decades.
Here’s a thread you might enjoy that will help you learn more about squash blossom necklaces. Can we share our squash blossoms?
Enjoy your beautiful gift!