This content was first published on IGR – Italian Gemological Review no. 15 in 2022. The information provided here is therefore current as of the original publication date.
The Asian Institute of Gemological Sciences (AIGS) has codified the grading standard dubbed Santa Maria for medium and high saturation aquamarines. In order to obtain an accurate hue, chroma and tone notation, the AIGS has established specific reference masters. The AIGS masters also show those aquamarines that, according to AIGS criteria, cannot achieve the Santa Maria grade, because they exhibit yellow and brown tones, despite their high saturation level.
The choice of the Santa Maria grade designation is explained by a reference to an extremely sought-after quality of aquamarines mined in Brazil and now almost completely depleted. Santa Maria de Itabira is located northeast of Belo Horizonte. In this municipality there are several pegmatitic bodies discordantly embedded in gneissic rocks of the Rio do Tanque sequence, which belong to the Guanhães gneissic-migmatitic complex. Specifically, the area has been providing impressive beryls in their aquamarine and heliodor varieties.
Interestingly, to assign the Santa Maria quality grade it is not necessary to determine its provenance from the traditional Brazilian source. It actually can be applied to any beryl, variety aquamarine, that meets the requirements of the master, regardless of its provenance. «The launch of the Santa Maria color code is yet another important initiative after launching our Jedi spinel reports last October» said Kennedy Ho, Chairman of AIGS. «Trade names such as pigeon blood and royal blue have been used for centuries by gem traders to describe ideal colors implying value and rarity. Yet these trade names are often ambiguous with definitions varying between buyers and sellers alike. By transforming trade names into an industry standard through reports graded by third-party objectivity, AIGS aims to reduce such ambiguity».
Gem News published on IGR – Italian Gemological Review #15, Autumn 2022
