Diamonds are among nature’s most precious and beautiful creations.
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Figure 19. A simplified map of the São Francisco craton, showing the areas covered by sediments of the geological formation called the Espinhaço Supergroup. The locations of several diamond districts are also shown, including Diamantina, Grão Mogol, and Serra do Cabral in Minas Gerais, and the Chapada Diamantina region (Lençóis, Palmeiras, Andaraí, Mucugê and Morro do Chapéu) in Bahia.
Figure 16. This map shows the Abaeté and nearby river systems in Minas Gerais that have produced large diamonds for many years. Again, the value shown next to each symbol represents the carat weight of the rough crystal found at the location. Discoveries of colored diamonds are indicated by colored symbols. The rivers shown on the map, some of which flow into the Tres Marias reservoir, are all located within the southern portion of the São Francisco River basin.
Figure 14. The Alto Paranaíba region of western Minas Gerais has produced large diamonds along river systems near the towns of Coromandel and Romaria. The symbols indicate where individual large diamonds were found; the value shown next to each symbol represents their carat weight. The site where the famous Star of the South diamond was recovered in 1853 along the Bagagem River is indicated in the lower left corner.
Figure 11. This diagram illustrates the kinds of secondary diamond deposits found along the Santo Inácio River in Minas Gerais—alluvial and colluvial deposits along the river channel, occasional kimberlite pipes (often unrecognized because they are deeply weathered and covered by younger sediments), and sedimentary conglomerates exposed on the adjacent hillsides.
