Natural-Color Pink, Purple, Red, and Brown Diamonds: Band of Many Colors

Abstract

iamond is one of Earth's most extraordinary materials. It represents the pinnacle for several material and physical properties. As a gem, however, it is the near-perfect examples-diamonds attaining the D-Flawless distinction-and those with imperfections resulting in a vibrant or surprising color that create the most enduring impressions. Fancy-color natural diamonds are among the most highly valued gemstones due to their attractiveness and great rarity. The 18.96 ct Winston Pink Legacy, with a color grade of Fancy Vivid pink, recently made history by selling at over $50 million, its $2.6 million per carat price an all-time high for a pink diamond (Christie's, 2018). This article is the third in a series of studies on natural colored diamonds: Breeding et al. (2018) discussed the color origin of green diamonds, and Eaton-Magaña et al. (2018) dealt with blue/gray/violet diamonds. Here we summarize the color origin of orangy pink, purplish pink to pinkish purple, brownish pink to pinkish brown, pink, red, purple, and unmodified brown diamonds. Although this article covers a wide variety of color descriptions compared to, for example, the first article in the series, which was limited to natural diamonds with only green as the

Naturally Colored Yellow and Orange Gem Diamonds: The Nitrogen Factor

“…Similar to cape diamonds, the platelet, 1430 cm -1 , and 1450 cm -1 fea- tures as well as occasional H-related features are seen in all H3 diamonds. In contrast, brownish yellow and orange diamonds colored by the combination of H3 and a 550 nm visible absorption band are extremely consistent as type IaA diamonds with moderate amounts of total nitrogen, a weak platelet peak, and the presence of amber centers (Massi et al, 2005;Eaton-Magaña et al, 2018b) that mark the plastic deformation related to the 550 nm band.…”

“…Diamonds grow deep in the earth's mantle, and by the time they are in a faceted form they generally have no remaining unique characteristics from the geographic region (i.e., country of origin) in which their kimberlites came to the earth's surface. Nonetheless, certain mines or regions have produced many of the blue (Cullinan mine, South Africa), green (Brazil and Guyana), and pink to red diamonds (Argyle mine, Australia; Lomonosov mine, Russia; Smit and Shor, 2017;Breeding et al, 2018;Eaton-Magaña et al, 2018a, 2018b. This correlation has more to do with the unique geological environment required to produce those colors.…”

“…The final article will look principally at colorless diamonds and the rest of the D-to-Z scale. We wish to conclude this exploration of fancy-color natural diamonds by providing a brief summary and comparison of all five diamond color groups: green (Breeding et al, 2018), blue/gray/violet (Eaton-Magaña et al, 2018a), pink/purple/red/brown (Eaton-Magaña et al, 2018b), white/black (Eaton-Magaña et al, 2019) and yellow/orange (this article). Table 2 lists the major causes of color in descending order of abundance within each of the color groups in the diamonds seen at GIA.…”

“…To our knowledge, data from such a quantity of yellow and orange diamonds has never before been compiled in a publication. As with the previous articles in this series (Breeding et al, 2018;Eaton-Magaña et al, 2018a, 2018b, our goal is to provide a detailed account of the gemological and spectroscopic characteristics of natural yellow and orange diamonds colored by different nitrogen-related defects. For the spectroscopic and abundance evaluations, we used a random, representative sampling of 500 diamonds, including both yellow and orange stones.…”

Natural-Color D-to-Z Diamonds: A Crystal-Clear Perspective

“…Therefore, we finish this series (Breeding et al, 2018(Breeding et al, , 2020Eaton-Magaña et al, 2018a, 2018b by examining diamonds with very little to no color at all-those on the D-to-Z grading scale. Although they make up by far the largest proportion of stones submitted to GIA, detailed statistics of D-to-Z diamonds have never been presented before.…”