Book excerpt: "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.