From valuable and beautiful gemstones such as sapphire, opal and diamond to fascinating and unusual crystals, rock formations and organic minerals, this book profiles the geological wonders of the world. Minerals and Gemstones is an ideal reference for beginners and experts alike, featuring 300 different entries. Each gemstone or mineral is illustrated with a clear and informative colour photograph, accompanied by informed and accessible text. For easy reference, each entry includes a table of information with chemical and crystal data, hardness on the Mohs scale, density, colour and fluorescence.