MINAS GERAES (i.e., "general mines"), popularly MINAS, an inland State of Brazil, covers an area of 221,861 sq. m. upon the great Brazilian plateau. Among the Brazilian States it is fifth in size and first in population—estimated at 7,442,243 in 193o.
The surface of Minas Geraes is broken by mountain ranges and deeply eroded river-courses, the latter forming fertile valleys shut in by partly barren uplands, or campos. The principal mountain ranges are the Serra da Mantiqueira on its southern frontier and its north extension, the Serra do Espinhaco, which runs parallel to the Serra do Mar, or coast-range, and separates the inland or campo region from a lower forested zone between the two ranges. Most of the wooded district south of the Mantiqueira belongs to the States of Sao Paulo and Rio de Janeiro, but east of the Espin hag° it belongs to Minas Geraes and extends eastward to the Serra das Aymores, on the frontier of Espirito Santo. This zone has an abundant rainfall, dense forests and a fertile soil. It is drained by the Doce, Mucury, Jequitinhonha and Pardo. The southern part of this region is well populated, and is covered with coffee and sugar plantations. On the western frontier a northern extension of the great central chain of Goyaz forms the water-parting between the drainage basins of the Sao Francisco and Tocantins, and is known at different points as the Serra do Paranan, Serra de Sao Domingos and Serra das Divisoes. South-east of this chain, be tween the headwaters of the Parana and Sao Francisco, are the Serra da Canastra and Serra da Matta da Corde, an irregular chain of moderate elevation running north and south. The highest elevations in the State, so far as known, are Itatiaya (8,898 ft.) in the Serra da Mantiqueira. and Caraca (6,414 ft.), near Ouro Preto, in the Serra do Espinhaco.
Less than 'co m. from the city of Rio de Janeiro and 6o m. from the coast is the source of the Rio Grande, the larger of the two rivers that form the Parana. North and parallel with its course is a low watershed, which separates its drainage basin both from that of the Sao Francisco and from that of the Parnahyba, the northern confluent of the Parana. The latter rises on the west ern slopes of the Serra da Matta da Corde. The central and greater part of the State, is included in the drainage basin of the upper S5.o Francisco. The climate of Minas Geraes is characterized by high sun temperatures and cool nights, the latter often dropping below the freezing point on the higher campos. The mean annual temperature is about 85° in the Sao Francisco valley, 77° on the campos of the south-east and 70° on the campos of the west. The year is divided into two seasons—wet and dry—the former lasting from November to May. This division is not so clearly
marked in the south, especially in the "matta" (forest) regions, where the rainfall ranges from 59 to 65 inches. There is much malaria in the wooded districts of the east ; and on the higher campos, where the daily extremes of temperature are great, lung and bronchial diseases are common. Some of the high plains, however, as at Barbacena, serve as health resorts for the coast districts.
Minas Geraes is a mining State, though the mining industry has lost much of its importance through the decline in the output of gold and diamonds. Gold is widely diffused, and abandoned "washings" all over the State show how general the industry was at one time. There were in 1908 five deep mines worked by Eng lish companies and one by a French company. One of these, the Morro Velho mine, belonging to an English company, is not only the deepest gold-mine in existence (over 6,126 ft. in 1920), but it has been worked since 1725, and since 1835 by its present owners. Silver is not mined by itself, but is found in combination with gold. In 1908 a rich goldfield was discovered in the northern part of the State, 5 m. from Montes Claros, in the valley of the Verde Grande river. There are many rich deposits of iron ores in the State, but they produce only a small quantity of charcoal iron for local consumption. Manganese ore is mined, and 311,00o tons were exported in 1926. Minas Geraes is most widely known for its diamonds, which are found in widely separated parts of the State. The largest and most productive field is that of Diamantina (q.v.) on the head-waters of the Jequitinhonha river, where dia monds were discovered about 1725, and where the celebrated "diamond reservation"—an oval-shaped territory 8 leagues wide by 16 leagues long, with Tejuco, now Diamantina, very nearly in the centre—was established in 1730. The mines became crown property, gold-mining was forbidden, and no one was permitted to enter the reservation without a licence. The State monopoly was abolished in 1832, and mining has since been carried on by private enterprise. John Mawe estimates that the annual product was 1,000 ounces during the first 20 years, and Castelnau puts the value of the total output down to 1849 at 300,000,00o fr. No es timate can be made of the contraband, which must have been large. A great decline in the output occurred during the last half of the 19th century ; while several new fields have been discovered since 1908, the output is not large. Other valuable stones, the topaz, chrysolite, aquamarine, amethyst and tourmaline are found.