Jimmy,
Martin brought the answer..it's the bloom which may or may not be enhanced by the predominant wave lengths of the available light when the picture was taken.. Ideally in summer near sunset at northern latitudes....the fig skin hairs will also play a role in this with its crossed reflexions.
the most difficult exercise is to bring 'green bloom' to the picture and apparently this can only be done in the southern hemisphere at lower latitudes.
Let me give you another one which is slightly different, may be a deeper blue skin perception.
As regards to names I am a bit scared to pass them to you as my figs are 'ficus non grata' in America!!
with their name on hand 'echelon' may grab the poor fruit and...
Well, as you are a friend, I will tell you,..the big one is known by 'donkey's balls' .. if they grab, that's their problem!
The smaller fruit is a popular and inoffensive black Smyrna, one of the very best to my palate.
Francisco