"Brazil was the leading world producer of gold and of diamonds between the mid-18th century and the mid-19th century. At the present time, it is the leading world producer of iron ore, tin and niobium, and an important producer of manganese, aluminium, silicon, tantalum, rare earths, graphite, magnesite and countless other ores.....Brazil is the leading world producer of tourmaline (of all colors), of quartz (colorless, rutilated, amethyst and agate), of beryl (aquamarine, morganite and heliodore, and the second ranking world producer of emerald), of topaz (imperial, blue and colorless), alexandrite, euclase, phenakite and many others" INTRODUCTION.

Liza Urla is the author of the jewelry blog, Gemologue https://gemologue.com/tag/jewelry-blog

"Gems and Gemstones" features nearly 300 color images of cut gems, precious and semiprecious stones, gem-quality mineral specimens, and fine jewelry to be unveiled in the new Grainger Hall of Gems at the Field Museum in Chicago.

Simon & Schuster's Guide to Gems and Precious Stones provides both the connoisseur and the casual collector with a compact, easy-to-use volume describing more than 100 rare varieties of minerals whose beauty and mystery have possessed our imaginations from time immemorial. More than 450 brilliant photographs accompany profiles of each gem, covering such aspects as appearance, physical properties -- density, hardness, refraction -- occurrence, and how to judge quality and value. Additional sections describe the process of cutting gemstones and the techniques professional gemologists use to evaluate a stone's weight and optical properties. Detailed and comprehensive, this book is essential for anyone interested in the study of gems and precious stones.