Name/Title
Emerald in QuartzEntry/Object ID
2023.7.53Description
Formula:Be3Al2(Si6O18)
Crystal System:Hexagonal
Name:Emerald has priority over beryl as a mineral name. Emerald was known in antiquity and was prized as a gem. In the 1790s, Louis Nicolas Vauquelin, the discoverer of chromium, demonstrated that emerald and beryl were essentially the same chemical compound and that emeralds, sensu strictu, contained chromium. Nonetheless, emerald continued to be listed as the preferred species name for many decades and emerald finally began to be used as a variety name for beryl by the 1830s. New emerald reports referring to ordinary green or even blue beryl persisted in the amateur literature into the twentieth century. In the latter twentieth century, it was discovered that some emeralds contain more vanadium than chromium.
A variety of Beryl
A green gem variety of beryl, highly sought after as a precious gemstone. The majority of the world's gem-quality emeralds come from the Muzo area of Colombia.
The colour of emerald is caused by trace amounts of a chromophore such as trivalent chromium or trivalent vanadium.
The emerald occurrences and deposits are classified into two main types:
(Type I) Tectonic magmatic-related with sub-types hosted in: (
IA) Mafic-ultramafic rocks (Brazil, Zambia, Russia, and others);
(IB) Sedimentary rocks (China, Canada, Norway, Kazakhstan, Australia);
(IC) Granitic rocks (Nigeria).
(Type II) Tectonic metamorphic-related with sub-types hosted in:
(IIA) Mafic-ultramafic rocks (Brazil, Austria);
(IIB) Sedimentary rocks-black shale (Colombia, Canada, USA);
(IIC) Metamorphic rocks (China, Afghanistan, USA);
(IID) Metamorphosed and remobilized either type I deposits or hidden granitic intrusion-related (Austria, Egypt, Australia, Pakistan), and some unclassified deposits
Emeralds from the Panjshir Valley in Afghanistan differ slightly in gemological properties from those of other origins and can be distinguished and identified by their serrated, three-phase inclusions containing multiple crystals, type I water-dominated near-infrared spectral absorption, and medium to low Li and Cs, medium to high Sc, and medium to low Na. It is lighter in color, lower in alkali metals, and more complex in gas-liquid three-phase inclusions than the emeralds from the Swat Valley, Pakistan.Location
Location
Display Case
FS-11Room
Frieda Smith HallBuilding
Crater Rock MuseumCategory
PermanentMoved By
Curtis GardnerDate
December 27, 2023