Yes, it`s interesting, but there are TWO lakes and the other lake has a little bit different colour which seems to be nearer in direction to "blanc". Look at my photo of Mont Blanc Group with Lac Blanc. I do either not understand why the mountain "Aiguille verte" got its specific colour! My photos show it in white or red ("Alpenglühen")!
By the way, in the National Park "Aiguilles Rouges" (this name is absolutely ok) exist a "Lac blanc", "Lac bleu", two "Lacs noirs" but not at all a "Lac vert"!!