This book compiles reviews of both fundamental and applied research in physics and materials science, focusing on the existence, formation mechanisms, and artificial synthesis of versatile, nature-inspired crystals. It aims to highlight the development and application of advanced crystals with novel polymorphism and microtextures, resulting in the innovation of completely new and unexpected functionality. The book encompasses five main topics; the first three focus on fundamental research in mineralogy in the areas of polymorphism and microtexture in biological environments, crystallographic structure, and nucleation and growth.