History of Emeralds in Brazil
The first ever search of emerald in Brazil began centuries ago in the year 1554 as an expedition led by Bruzo Espinoso and a Jesuit priest. This was shortly followed by another expedition by Martin Carvalho in 1567. However none of these expeditions showed any promising result. However in 1572 the first major breakthrough occurred when Tourinho found what he called “Baked Emeralds”. Years later, in 1612, Marcos de Azeredo Coutinho found emeralds, but he died without naming the locality from where he found those green stones. A search then started to find Coutinho’s secret locality of the emeralds. In the year 1713 this feat was achieved but it turned out that the green stones were green tourmalines and not emeralds. Years later, the source of Brazilian emeralds was finally located to be in Brumadinho in Bahia and Rio Doce area.
Geologic Occurrence of Brazilian Emeralds
The emerald crystals in Brazil were found in cavities in altered marble capping a mountain. The crystals were much flawed and in shape of hexagonal prisms with basal pinacoids and the edges truncated with small pyramidal faces. Later, fine quality emeralds were found associated in a mica schist in Carnaiba Mountains near Campo Formoso in Bahia. Emeralds were also found in the famous Minas Gerais, known for abundance of rare minerals.
Emerald-producing areas in Brazil
Currently emeralds are found in the following regionss: At Itabira, Capoeirana, Santana dos Ferros (Minas Gerais), Fazenda das Lajes, Santa Terezinha de Goias, Pirenopolis, Porangatu, Fazenda do Pombo, Acude de Sossego, Brumado, Carnaiba, Salininhas, Socoto, and Taua.
Properties of Brazilian Emeralds
Emeralds from Brazil have a slightly higher specific gravity from 2.68 to 2.76, and the refractive index varies from 1.573 to 1.595 with a birefringence of 0.05 to 0.08. Most of the emeralds are a pale yellowish green resembling green beryl (which is the parent family of emerald), but its chromium content puts it under the emerald category. Recently, new mining has been yielding dark green, deep green and grass green emeralds similar in quality to their Zambian counterparts.
Filling of Brazilian Emeralds
Since most Brazilian emerald are very pale in colour but have excellent transparency, they have been prone to a number of filling treatments to induce a darker colour, and most have been successful. However, over due course of time, these “fillers” got removed from the gemstone by normal wear and tear leaving the emeralds undesirable and weak.
Some Brazilian Emeralds from our inventory: