Statistics of Size, Color and Enhancement of Copper-Bearing Tourmaline from Brazil
Fig. Par11 Statistics on certified copper-bearing tourmalines from Brazil, sorted according to color and size. They were tested and certified in the GRS laboratory in the years between 2004 and 2008. The stones listed are gem-quality faceted stones; both heated and unheated (see Fig. Par12). The majority of these gems are below 10 ct in size. Larger gem-quality Paraiba tourmalines over 10 ct are extremely rare and purple colors such as found in Mozambique in this size category did not appear in our laboratory (compare Fig. Par08).
Fig. Par12 Statistics on the number of heated and unheated copper-bearing tourmalines from Brazil (Paraiba or Rio Grande do Norte) in different color categories. The majority of “Paraiba”-tourmalines from Brazil was found to be heated. Most of the unheated Paraiba tourmalines are from the category of mixed green and blue colors. None of the pure “neon”-blue colors that came to the GRS laboratory for testing were unheated. A higher percentage of Brazilian tourmalines were unheated in comparison to the Mozambique tourmalines (See Fig. Par07).
Statistics of Size, Color and Enhancement of Copper-Bearing Tourmaline from Brazil
