I am not an expert on telling the difference between natural/real and manmade crystals, so I cannot speak to that for this necklace. I see complaints about it not looking like the picture, and they are right, but that is typical of crystals in general. I looked up yellow carnelian, and the pictures online look almost identical to some of what other reviewers are showing, and it does not always have stripes or bands on it, so one should not buy this convinced it will look that way. One should look it up first to see if this is what you might want.
With that said, I thought mine was a nice piece. Mine does have some striping or banding on it on one end, but it needs a good light on it and will not show in a picture well. It does look exactly like what I am seeing online either way with the coloring and look to it. I love crystals, including ones with flaws if they are natural as that is the way they were created, so this necklace is perfectly fine for me. Use your judgement if you would prefer something that looks a little more "perfect." It comes with a nice leather chain that a lot of crystal necklaces come with.