Note: This is Volume 2 of Amateur Gemstone Faceting, containing Chapters 10 to 20. To track down Volume 1, search for "Amateur Gemstone Faceting Volume 1: The Essentials." Have you ever gazed in wonder at a faceted gemstone, at the ever-changing interplay of light, colour, and sparkle, and asked yourself how such a thing could come into being? Gemstones have been a source of fascination, mystery, and power for millennia, yet it is only in the last few decades that the tools and knowledge for creating these tiny miracles have been available to the average person. In this second volume, amateur faceter Tom Herbst helps you expand your faceting horizons. You will learn about the optics and mathematics behind the magic of gemstones. Subsequent chapters on the properties and treatment of common gem materials will help you identify and make the most of your valuable rough. To really expand your horizons, try faceting on your computer, visualizing gemstones before committing the stone to the lap. Nothing can match the satisfaction of creating and cutting your own unique gem cuts. Chapters on general design principles and a specific case study should help you on your way. Finally, faceters are inveterate tinkerers, and the concluding chapter lays out ideas for multiple do-it-yourself projects, including instructions for building a precision digital angle encoder for your faceting machine. Happy cutting, and may your horizons expand before you. Chapter 10 - Gemstone Mathematics and Geometry Introduces the essentials of trigonometry needed for faceting, including tangent ratio scaling. Discusses gemstone symmetry and maximizing yield from a piece of rough. Chapter 11 - Gemstone Optics Explains the wave nature of light and how its interaction with matter produces colour, refraction, internal reflection, and luster. Chapter 12 - Gem Material Properties Explains the optical properties of gemstones (colour, refractive index, dispersion, saturation, colour change, birefringence, and pleochroism), as well as their physical characteristics (density, hardness, crystal structure, cleavage, and inclusions). Chapter 13 - Gemstone Treatments Explains the procedures and ethics of gemstone treatments, ranging from heat and radiation to oiling and exotic techniques. Chapter 14 - Common Gem Materials Easy to read tables of properties for the most common gemstone materials, with a focus on faceting-related information. Chapter 15 - Faceting on Your Computer Use your computer t