Question: I am interested in **sources** (reference author, work, paragraph/fragment) describing the view ancient Greeks held about people of African descent. 

By that I mean those whom they called *Αιθίοπες* (Aithíopes), not the Egyptians or other North-Africans. 

Are there attestations of racism (strictly because of skin color) or admiration in ancient Greek works? 

Regarding admiration we have one account from Herodotos (3.20) who
states the following:

> 
> These Ethiopians, to whom Cambyses sent them, are said to be the
>  tallest and most handsome of all men. Their way of choosing kings is
>  different from that of all others, as (it is said) are all their laws;
>  they consider that man worthy to be their king whom they judge to be
>  tallest and to have strength proportional to his stature.
> 
> 
> <http://www.perseus.tufts.edu/hopper/text?doc=Perseus:text:1999.01.0126:book=3:chapter=20>
> 
> 
>

Answer: 
See
<http://department.monm.edu/classics/Courses/CLAS240/Africa/homeronethiopians.htm>
for a collection of quotations from Homer about the Aethiopians [which basically meant black, sub-Saharan Africans], who are referred to respectfully e.g.:

"Iliad 1.423-4 (Thetis is speaking to Achilles.)
Only yesterday Zeus went off to the Ocean River
to feast with the Aethiopians, loyal, lordly men,
and all of the gods went with him."

Another Example:
While Ovid was a Roman, his collection of stories the 'Metamorpheses' was written based on the Greek myths and shows the considerable influence from Greek culture normal among educated Romans. In the story of Phaeton, Ovid says that the Aethiopians became the colour they are because the sun once veered dangerously close to the Earth and permanently charred them black. This suggests he and his audience regarded being black-skinned as something sufficiently different from what they knew as the norm to potentially require explaining, but he does not suggest that blacks were intrinsically inferior to whites.
Aristotle mentions some descriptions in [Physiognomonica](https://archive.org/stream/worksaristotle00arisuoft/worksaristotle00arisuoft_djvu.txt) (look for Ethiopian. I'm not going to quote it... wow.)

Otherwise, I don't recall any mention of physical description of Africans (non-Northern Africans, i.e., Libyans, Egyptians, Cathaginians, etc.) in Thucydides, Xenophon or Plato, and only the reference from Herodotus you had. I don't see any reference to descriptions of physical attributes, but Herodotus also dicusses the [Persian invasian of Kush (Sudan)](http://www.livius.org/he-hg/herodotus/logos3_07.html).