It is definitely a variation of Tumbling Blocks otherwise known as baby blocks. I'm looking for that pattern but I'm getting pages and pages of "how to do tumbling blocks without a y seam" instead.
I have found for-sale variations of completed tops using both 4- and 9-patch variations but no pattern yet!
Last year at the thrift store I found a rather nice unfinished baby block top in early 80s cranberry, maroon and pink (it works). I haven't quilted it down yet but I've spent quite a bit of time looking at quilting designs for it.
Edit: It would be pretty easy to print out a Tumbling block pattern and fold it to get your diamond shapes. Remember to add seam allowances!