J. C. (Hanco) Zwaan
ABSTRACT: Demantoid garnets from Antetezambato, northern Madagascar, contain a cha
teristic inclusion suite typical of a skarn occurrence. Unlike demantoid from the classic depo
in the Ural Mountains, Russia, and from other serpentinite-related occurrences, the stones fi
Madagascar do not contain 'horsetail' inclusions, but instead host groups of small, rounded diop:
grains, fluorapatite, dolomite, calcite, quartz, pyrite and wollastonite, as well as rare native bism
Partially healed fissures contain two-phase fluid inclusions (with H,O and a gas bubble) of vary
salinity. Negative crystals, commonly large and empty, sometimes also contain H,O. Pronoun
growth features and parallel hollow tubes are also present. Demantoid from Namibia likewise hi
skarn origin and shows some similar internal features, as well as some that are different, such as
common presence of fluorapatite and small multiphase fluid inclusions, along with the absenc
large negative crystals and native bismuth. A review of previously advocated methods for geograt
origin determination of demantoid based on chemical fingerprinting alone shows that this techni
is applicable only to stones with a nearly pure andradite composition when differentiating Malag
and Namibian localities. In such cases, elevated traces of Mn are indicative of a Namibian origi
The Journal of Gemmology, 38(1), 2022, pp. 64-79, https://doi.org/10.15506/JoG.2022.38.1.64
• 2022 Gem-A (The Gemmological Association of Great Britain)
merald, the green chromium-bearing variety
of beryl (Be;Al,Si,O¡8), has been one of the
most sought-after gem materials throughout
history. Since the 17th century, emeralds
from Colombia have gained the highest reputation and
market importance, but other sources have also emerged
in recent decades, such as Zambia (e.g. Kafubu),
Madagascar (e.g. Mananjary) and Ethiopia (Shakiso)
in Africa, as well as Pakistan (Swat Valley), Afghanistan
(Panjshir [Panjsher] Valley) and China (Davdar in the
Xinjiang Uyghur Autonomous Region) in Asia. Stones
from the Panjshir Valley in Afghanistan are commonly
described as resembling Colombian emeralds in terms
of colour, quality and even inclusion features (Bowersox
et al. 1991; Schwarz & Pardieu 2009). Their reputation
is underscored by the fact that a 10 ct Afghan emerald
was sold at auction in 2015 for USD2.275 million (Chris-
tie's 201 5) -equivalent to the highest recorded per-carat
price for any emerald from a non-Colombian locality.
The Swiss Gemmological Institute SSEF regularly
receives emeralds from Afghanistan for testing, quite
often in impressive layouts and settings. In the past,
determining their geographic origin was in most cases
quite straightforward. However, in early 2017 this
changed, and since then we have analysed more than
100 samples of an apparently new type of emerald from
the Panjshir Valley in Afghanistan. (Hereafter in this
article these stones will be referred to as 'Panjshir type
I' emeralds.) They have been submitted to SSEF by