A firm, flexible material. Can be found in some animal horns, plates, shells, and ridges.
— In-game Description

Keratin is a resource used in making the Blood Extraction Syringe and Cementing Paste among other things. Keratin is harvested from certain creatures by punching them, using the Stone or Metal Pick, the Stone or Metal Hatchet, or carnivores. The most effective way being the Hatchet or Sabertooth. Dinosaurs with large shells or horns will usually produce Keratin when harvested. 4 Keratin/Chitin can be combined with 8 Stone in the Mortar and Pestle or 16 Keratin/Chitin can be combined with 32 Stone in the Chemistry Bench to produce Cementing Paste.