2026

Emeralds from the Minas Canaã, Minas Gerais, Brazil

By Isabelle Beney, SSEF, first published in Facette 30 (March 2026)

Figure 1: Images of emeralds from Canaã. Photo: SSEF.
In September 2024, the SSEF had the privilege of testing a few emeralds from the Mina Canaã, some of which exhibited exceptional qualities. Impressive in terms of weight, clarity and colour, these stones had further been spared any treatments, thus meaning their attributes were entirely natural.

Background

The Mina Canaã is situated south-east of Itabira, in the Brazilian state of Minas Gerais. Although the deposit which the mine exploits is already well known (there are other known emerald producers also situated in the same area), as with any geological deposit, there is spatial variety in terms of the products mined and their physical and chemical attributes. The emeralds at the Mina Canaã are extracted from phlogopite schist host rock – iron-bearing surroundings that ensure emerald is not the only form of beryl that is found at the locality; note, aquamarine is also found at Canaã.
Figure 2: Microphotos of emeralds from the Mina Canaã. Note the fine growth needles (almost ‘rain’-like) from different perspectives in images A + D, fluid inclusions in B + C, and the zoning visible in B + D. Photos: SSEF.

Properties

Chemically speaking, the emeralds analysed from the Mina Canaã are comparatively iron rich, with the concentrations of this trace element always reading one order of magnitude higher than chromium, and two orders of magnitude higher than vanadium. In terms of microscopic observations, what sets these stones apart from most other emeralds is their comparative lack of large inclusions and fissures, typically common in emeralds regardless of source. Furthermore, their unusual clarity was not due to enhancements from any treatment processes, making these stones particularly exceptional. The few microscopic observations made were mostly of short and fine needle-like growth channels, usually oriented parallel with the optic axis (see Figure 2, A + D), and strong colour and growth zoning, oriented perpendicular to the optic axis (see Figure 2, B + D). Few two-phase inclusions were observed (e.g., Figure 2C). Being able to examine exceptional material like these emeralds is one of the biggest privileges to have as a gemmologist. Here at SSEF we are grateful to have had this opportunity.