PROBLEM

I just see a grass block..? 

What's the exact problem? Is it the little grey bits in the grass block? Because those are supposed to be there, they're like pebbles in the dirt.

I think he sees colors differently, so the dirt looks purple.

Don't you guys see the little green and purple when I slowly look up and down on the blocks?

No, I do not.

if we are not seeing it. You may have some hardware graphics issues.

Can you record your screen with something else then scteencapture? Like a phone?

Can you please clarify on what issue you're having? I cannot see it in the posted video.

Please record your monitor with a camera or something like that. The video looks fine to me. (If it's a hardware issue, then playing back a video that looks fine to others would still cause the issue for you while it isn't visible to us).

Actually, a different test would be to watch someone else's video and see if it also happens there. Try, say, this one from Etho.