Apatites are ionic compounds which have high concentrations of hydroxyl ions, fluoride ions and chlorine ions. They are phosphate minerals which exist as igneous rocks, metamorphic rocks, sedimentary rocks and volcanic rocks. They could also be found as gem stones which are usually green or blue in color. Apatites are classified into hydroxyapatite, fluorapatite and chlorapatite. They form a major component of the bone material and tooth enamel. Apatites are the most abundant source of inorganic phosphorus, thus making them extremely useful in the fertilizer industry. This book aims to shed light on some of the unexplored aspects of apatites and the recent researches in this field. The various studies that are constantly contributing towards advancing technologies and evolution of this field are examined in detail. This book is a vital tool for all researching or studying apatites as it gives incredible insights into their structure, characterization and applications.