Iron-based materials, especially magnetite nanocrystals, have found extensive applications in many fields. Novel challenges focus on a deeper understanding of interactions between magnetite and biological macromolecules for developing further applications in diagnostic and treatment methods in medicine. Inspired by ferritin, the iron storage protein occurring in bacteria, plant, animal, and human cells, we developed an artificial ferritin-like material known as magnetoferritin. We present structural studies of magnetoferritin samples prepared using a controlled in vitro physicochemical synthesis. Considerable structural and size changes were observed by increasing the iron content and post-synthesis treatment. We propose the modulation of colloidal stability by using suitable solvents. Ultraviolet and visible spectroscopy, dynamic light scattering, colloidal stability measurements, infrared spectroscopy, and small-angle X-ray scattering methods were employed. The presented results aid in increasing the effectiveness of the various applications of magnetoferritin according to specific industrial requirements.