Diamonds are among nature’s most precious and beautiful creations.
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Figure A-1. Illustrations of the diamond faceting arrangements known in France by the mid-1700s. These were compiled by Denis Diderot, chief editor from 1745 to 1772 of the 28-volume Encyclopédie, ou Dictionnaire Raisonné des Sciences, des Arts et des Métiers, one of the principal works of the Enlightenment. This page is taken from his 1771 volume entitled Recuiel de Plances, sur Les Sciences, Les Arts Liberauz, et Les Arts Mechaniques (p. 732).
Figure 5. The Estrada Real, or “royal highway,” was the principal 18th century route to transport goods from Minas Gerais to the ports of Parati and Rio de Janeiro, a distance of several hundred miles, for shipment to Europe.
Figure 3. The 1494 Treaty of Tordesilhas effectively divided the South America continent between Portugal and Spain. The Cantino planisphere map, produced around 1502, shows the north-south Tordesilhas meridian line passing through South America, whose geography was still largely unknown. Courtesy of Biblioteca Estense.
Figure 2. This selection of diamonds recovered from the Abaeté River in Minas Gerais, weighing a total of 77.82 carats, is typical of the material being found today in Brazil’s alluvial deposits. Photo by Robert Weldon/GIA, courtesy of Giovani de Deus Borges.
Figure 1. The Portuguese Placa dos Três Militares, or Badge of the Three Military Orders, was made in 1789, and is now part of the crown jewelry collection of the Ajuda National Palace in Lisbon. The badge consists of Brazilian diamonds as well as emeralds and rubies, and it is designed in a way to conceal the metal mounting and emphasize the gems. Photo by Manuel Silveira Ramos, courtesy of the Ajuda National Palace.
Figure 2. A Raman spectrum of the inclusion with a radiation halo shows a strong peak at 972 cm–1 and smaller peaks at 575 and 415 cm–1, all of which correspond to monazite.
Figure 1. Left: This 0.49 ct Fancy pink brown diamond, measuring 4.11 mm wide, contains a monazite inclusion with a brown radiation halo. Right: A photomicrograph of the monazite inclusion shows the halo thickness of about 10–20 µm. The inclusion’s color is masked by the brown radiation stain, but it appears to be yellow or colorless. The dark feature extending from the bottom of the inclusion is a graphitized crack. Field of view 0.36 mm. Photos by Jian Xin (Jae) Liao (left) and Evan Smith (right).
