Nera is introducing Zeology Leather - chrome free, heavy metal free and aldehyde free. Join us in our sustainable ambition. Zeology Leather is now available! The Zeology leather tanning agent is truly sustainable and does not compromise on leather performance. It is just what you need to protect the Earth on the one hand, and still be able to create and use top quality leather for the manufacturing of premium leather goods, on the other. Nera stands for ‘NEw eRA’, as our tanning solutions mark the beginning of a new era: an era of truly sustainable leather manufacturing, throughout the entire leather value chain. We have developed Zeology as a responsible alternative to existing tanning agents. As a sustainable, zeolite-based tanning concept, Zeology is a gamechanger for the leather industry. Nera Tanning is a Royal Smit & Zoon company.