Oak galls are the result of gall wasps. Inside the galls are the insect's eggs and larvae. When the eggs are first laid, the galls will start as a lighter color, either green or yellow.

Chinese oak gall, Istrian gall, Marmora gall, galle corniculée, and Bazgendge (Fockeu) or Chersamel on Tamarix. In the manufacture of ink the galls used are: Cynips gallæ-tinctoriae Olivier, Cynips ...