Many diamond shaped UFO images are simply out-of-focus stars. This is not an out-of-focus star. Grade B.
I've seen this same orb-like daytime star where I live. (I think the blurry diamond shape is actually out of focus - but it's not a star). I watched it for several days near my house over about a 3 week period, off and on. It would move slowly and then suddenly show up in another part of the sky and then disappear altogether. I reported it to mufon and they told me it was a research balloon. I also saw it near Palm Springs once. There's a great video of one in Phoenix, as well.