This book examines and summarizes data on more than 40,000 diamonds from deposits in Russia's diamondiferous Arkhangelsk province. The geological data of diamond deposits includes the geological setting, ore body morphology and mineral composition. Investigation techniques employed include: Color Cathode Luminescence, Fourier Transform Infrared Spectroscopy, Electron Paramagnetic Resonance, Raman Spectroscopy, and Carbon Isotopy. The book provides a full description of the diamond morphology. The problems of a potential (mantle) diamond grade for deposits are considered, depending on the physical and chemical conditions involved in the genesis and growth of diamond crystals. Further, there can be a significant impact on the productivity of bodies and the properties of diamonds during post-crystallization metasomatic processes. In this book, the authors propose a diamond crystallization model for changes in diamond crystals within mantle metasomatic transformations, and identify the factors affecting the growth and dissolution of diamonds in the mantle. In addition, they describe the complex evolution of kimberlite from the mantle up to the Earth's surface. All of these factors affect the quality and quantity of diamonds in a particular diamond deposit, providing the basis for identifying optimal technological mining processes.