Herman Miller Eames Lounge chair Rosewood or Walnut?  

It's such a distinctively strange and pronounced grain
pattern for either species that it hardly matters.

Value
There's a difference in value.

Only to buyers
as shallow as the veneer.
But if you really want informed opinions, you'll need to post some high-res closeups. If someone were holding a gun to my head and told me I had to decide based on your picture, I'd have to say, "Rosewood... or walnut!"

I'm going
to say Walnut but agree it's a hard call

like tktoo said
post some very sharp close-ups of the grain in various places. Then maybe we can give you an answer.
And I think tktoo's point about it not mattering is that if it is this hard to tell which kind of veneer it is, the difference in value is going to be this hard to differentiate. A buyer who wants the look of Dalbergia Nigra is not likely to pay the big bucks for it if it doesn't "look" like itself, which happens sometimes.
finally: what is "italian walnut"?

Much better.
And quick, too!
It is definitely one of the six or seven various species that Herman Miller passed off as "rosewood".
Needs a good cleaning, oiling, and a wax, too.
Ka-ching!

Thanks
Thanks so much. I really appreciate it.

WWMD?
What would marie do?

Yours looks like cherry.
Not that there's anything wrong with that.
It's only a guess, but I doubt she'd have much good to say about it.

WWMD?
You've lost me here. Who's chair is cherry?

Woopsie!
Sorry for the confusion. It should have been clearer that my response was meant for Mark.
Your set is wrapped in a tropical species without doubt, IMO.

I vote Rosewood
I have had a Walnut chair and it's definitely light grained,unlike this which appears to be Rosewood begging for some moisture.Try orange or lemon oil.

Many thanks
I sure will. Thanks again you guys.

Rosewood
It looks like mine looks when it's starved for oil.