I don't know the name of the block, but it shouldn't be hard to duplicate. You have one large center square, two small squares and 10 HSTs the same size as the small squares. The blocks in this quilt have been set on point, which is what makes the blocks look more like diamonds than squares.
There is a quilt shop in Albuquerque, NM that has southwestern style patterns; however I don't know of anywhere to get free patterns. I believe it's called Southwest Decoratives, but it's been a while since I've been to the website.
You might try searching for seminole quilting patterns.