Ethiopia is now officially on the Paraíba tourmaline map. Independent investigations by the Gemological Institute of America (GIA) and Switzerland’s Gübelin Gem Lab have confirmed that a newly reported East African deposit is producing copper-bearing tourmaline that meets the widely accepted definition of Paraíba tourmaline.
The two respected laboratories announced Aug. 27 that they had separately examined samples from the Ethiopian deposit and reached the same conclusion. Their findings make Ethiopia the fourth known source of Paraíba tourmaline, joining Brazil, Nigeria and Mozambique.
The Ethiopian stones display an eye-catching palette ranging from vivid blue and bluish green to violet and purple. Many examples also show dramatic color zoning, creating fascinating variations within individual crystals.
Paraíba tourmalines burst onto the jewelry scene in the late 1980s after prospector Heitor Barbosa discovered intensely colored copper-bearing tourmaline near São José da Batalha in Brazil's Paraíba state. The material's almost neon blue appearance quickly made it one of the world's most coveted colored gemstones.
Whether or not a gem can be called a Paraíba tourmaline is not necessarily dependent on where the gem was mined, but what gives the gem its color. Under the definition used by the gemological laboratories, the designation can apply to tourmaline from outside Brazil when copper is the predominant coloring element.
This became relevant when copper-bearing tourmaline was subsequently discovered in Nigeria and Mozambique in 2001.
The Ethiopian discovery was initially reported in the trade earlier this year. Gübelin encountered stones in May with a chemical composition that did not match its reference material from Brazil, Mozambique or Nigeria. The laboratory subsequently assembled about 300 rough and faceted stones from multiple sources, including material obtained during a visit to Ethiopia. GIA began examining Ethiopian material in June and received a parcel of more than 100 rough and faceted samples in July for detailed research.
The laboratories also discovered something potentially valuable for identifying the new gems. Ethiopian Paraíba tourmaline has a distinctive chemical fingerprint, including elevated levels of vanadium, lead and gallium. These elements can help gemologists distinguish Ethiopian stones from material originating in the other three known sources.
Credits: Paraíba tourmaline from Ethiopia (top) includes a 7.64-carat faceted stone and an 8.70-carat rough stone. Photo (below) shows rough tourmaline stones from Ethiopia in a range of colors. Stones weigh from 4.20 carat to 10.95 carats. Courtesy of the Ferreira Group. Photo by Annie Haynes/GIA.