Carnaiba emerald deposit: The city of Campo Formoso is 77 Km North of Jacobina. The emerald deposits are located within an area of several kilometres diameter around the village of Carnaiba, the latter located 27 Km. SW of Campo Formoso or almost directly South about 9 Km from the village of Brejao das Grotas.  The "Rocha verde" or green rock outcrop at several points around Carnaiba from where emeralds are obtained. The formation of beryl is due to schist-beryl type deposits, which resulted from the chemical interaction between pegmatites and basic-ultrabasic rock.  These deposits are associated with two intruding proterozoic leucogranite massifs, the Serra da Jacobina volcano-sedimentary series and the older gneissic-migmatitic Archean basement. This deposit is divided into two districts: Carnaiba de Cima (Trecho Velho, Trecho Novo, Bica, Cabra pits) and Carnaiba de Baixo (Bode, Graviao, Lagarta and Formiga).

The emerald mineralization is related to intrusive albitic (albitic-oligoclase) or quartz-albitic pegmatoids or quartz veins crosscutting the serpentinites. Two kinds of veins are distinguish: the fracture veins or frinchas and contact veins or esteiras. The pegmatoids had caused the formation of a monomineralic, F-rich, biotite-rich zone, developed symmetrically on each flank of one vein. Emerald is intimately associated with the biotite-rich zone and sometimes is found within the vein.

In Santa Terezinha de Goiàs the pegmatite veins are absent. The pegmatites are directly linked to intrusive granitic bodies with limited local extension, or are related to important and extended pegmatite provinces. Emerald mineralization is located in biotite schists (biotitites), biotitete-talc-caarbonate and carbonate-biotite schists. The biotitites are the product of a metasomatic process which acted within the Santa Terezinha sequence.