I. Definition

Paraíba tourmaline refers to lithium - elbaite - liddicoatite colored by copper (and manganese). It has a rich variety of colors, mainly presenting as blue, green, blue - green to green - blue, etc. Among them, the highly popular variety is the one with high saturation and a unique "neon" effect (Figure 1). "Neon" is a description of the color of Paraíba tourmaline with a neon - like appearance.

Figure 1: A 3.14 - carat Paraiba tourmaline from Brazil. Photo provided by Pala International

The emergence of Paraíba tourmaline can be traced back to 1982, when the legendary mine owner Heitor Dimas Barbosa discovered this type of tourmaline (Figure 2). Since 1982, the mining area where Heitor discovered Paraíba tourmaline has been named the Batalha mine. In 1987, this mining area produced a small amount of tourmaline with a bright blue tint for the first time. In the same year, Heitor published a paper announcing the discovery of this gemstone.

The only currently producing Paraíba tourmaline mine is the Mineracao Terra Branca (MTB) mining area in the neighboring state of Rio Grande do Norte. It is located near the village of Parelhas, at the border with the state of Paraíba. This mining area was discovered in 1991 and was called the Mulunga mine at that time. It was taken over by MTB in 2000 (Figure 3).

 Figure 2: Heitor Dimas Barbosa holding an electric - blue Paraiba tourmaline crystal. The photo was taken in the 1990s

Heitor Dimas Barbosa was the first to discover Paraiba tourmaline and is known as the "Father of Paraíba". The crystal he is showing weighs over 10 grams. The color of this crystal also shows why high - quality Paraiba tourmalines from Brazil are so hard to come by. Photo provided by Heitor Dimas Barbosa.

Figure 3: There are many small Paraiba tourmaline crystals in the broken rocks in the wheelbarrow, which can be cut into various beautiful cuts. Photography: Andrew Lucas, copyright belongs to GUILD Gem Academy, authorized by MTB.

II. Evaluation Criteria

Based on the blue and green hues, the colors of Paraíba tourmalines are classified as Blue (blue), Green (green), Bluish Green (blue - green), and Greenish Blue (green - blue) by Guild Gem Laboratory. For Paraíba tourmalines whose colors can reach Neon (neon), Guild Gem Laboratory will add the description of Neon (neon) before the color. Currently, the commercial names of Paraíba tourmalines that Guild Gem Laboratory can issue include Neon Blue (neon blue) and Neon Green (neon green).

Neon Blue/Neon Green is the color rating given by Guild Gem Laboratory to Paraíba tourmalines with a neon - like appearance (Figure 4 and Figure 5).

Figure 4: Paraíba tourmaline rated as "Neon Blue"