Raw emerald stones from Swat, Pakistan. Photography: Deng Kaiyin; Copyright © Guild Gem Laboratory.

When it comes to emeralds, what most people think of first is often the Colombian emeralds with a mining history of nearly a thousand years. However, they may not know that a new star from Pakistan in the emerald world is gradually shining in the market. As a well - proven rising star, Pakistani emeralds have attracted the attention of thousands of fans with their highly saturated green color. In the 1980s, Pakistani emeralds became famous for their top - notch color quality. Recently, Pakistani emeralds, which had been out of the domestic market for many years, have reappeared. Their mystery has made many emerald enthusiasts yearn for them. Today, let's uncover the mysterious veil of the Swat emeralds from Pakistan together.

Faceted gemstone of vivid green emerald from Swat, Pakistan. Photography: Deng Kaiyin; Copyright © Guild Gem Laboratory.

Explore the Mining Area History

The Swat Valley in Pakistan is one of the earliest known emerald mining areas to mankind, with a history spanning over a thousand years. In 2000, when French scientists Giuliani et al. were sorting out the ancient French royal jewels, they conducted an oxygen isotope analysis on the emeralds inlaid on a pair of ancient Roman earrings dating back 2,500 years to trace their origin. The research results confirmed that they originated from the Swat Valley in Pakistan (Giuliani, 2000). Considering the prosperity of the Gandhara Kingdom* at that time, it can be inferred that as early as BC, people had already started mining Swat emeralds and spreading them along the Silk Road, much earlier than the discovery and use of Colombian emeralds.

The geographical location of Pakistan. The pictures are sourced from the Internet.

Due to the abandonment of the Silk Road, the emerald mines in Pakistan were gradually forgotten and once disappeared from the scene. It was not until 1958 that local shepherds accidentally discovered this verdant treasure on a hillside and presented it to the then crown prince. Only then did the Swat emerald shine on the world stage again. The four main emerald mining areas in Pakistan are the Swat Valley, Malak and Mohmand, Bajaur, and Khaltaro. Among them, the most important Swat Valley is located on the southern edge of the Hindu Kush Mountains, which is an extension of the Himalayas. Some of the mining sites with the largest production in this mining area are scattered along the northeastern border of Mingora Town. The harsh climate conditions have greatly increased the difficulty of emerald mining. For more than 70 years, the local people have been safeguarding this natural treasure using the most primitive manual mining methods. Since 1960, the Pakistani government has started to control the exploitation of the newly discovered mines in the Himalayas.

The intact crystal shape, rich color and high clarity make this bag of emeralds from Pakistan highly valuable.

Photography: Andrew Lucas; Copyright © Guild Gemology Education.

Since the 1970s, the Swat emerald deposit in Pakistan has gradually become one of the important production areas of high - quality emeralds in the world. The output increased from 5,000 carats in 1978 - 1979 to 40,000 carats in 1987 - 1988, with 40% being high - quality or extremely high - quality emeralds (Kazmi et al., 1989). Among the total 400,000 carats of emeralds produced during 1996 - 1999, 60% - 70% were high - quality emeralds (Khan and Kausar, 2010).
The core area of the Gandhara Kingdom includes the eastern part of present - day Afghanistan and the northwestern part of Pakistan. It is located in the Hindu Kush Mountains, and most of its population lives in the valleys formed by the alluvial of rivers such as the Kabul River, the Swat River, and the Indus River.

Overview of Mine Geology

Regional Geological Map of the Swat Area in Pakistan (Adapted from Kazmi et al., 1984)

The emerald deposits in Pakistan are mainly found in the ophiolite melange formed during the collision of the Indian and Asian continental plates in the Cretaceous and Tertiary periods. The emerald deposits occur in the suture zone. There are two main gem - quality emerald mining areas in the Swat area of Pakistan, namely the Gujar Kili village and the emerald mining area north of Mingora (Kazmi et al., 1989). In the Swat area, emeralds often co - exist with fuchsite and dark green chromium - rich tourmaline. They are found in the limonitized shear zones surrounded by talc - carbonate country rocks penetrated by fine quartz veins. The emeralds are scattered in sac - shaped and nest - shaped blocks with a diameter of about 5 - 15 cm, distributed in a scattered or drusy form. The emeralds in this mining area can also occur in the strongly broken magnesite rocks filled with reticular quartz veins, accompanied by fuchsite and chromium - rich tourmaline (Kazmi et al., 1986).

The most important Swat mining area in Pakistan. The picture is provided by Mr. Hayat from Pakistan.

Local miners are extracting emeralds in the tunnel. The picture is provided by Mr. Hayat from Pakistan.

Emeralds can be seen on the ground of the mine pit. Their green color forms a sharp contrast with the light gray of the parent rock. 

The picture is provided by Mr. Hayat from Pakistan.

Ore containing emeralds. The picture is provided by Mr. Hayat from Pakistan.

Basic Properties

Tubular inclusions; Field of view: 1.09 mm. Photography: Sun Xueying; Copyright © Guild Gem Laboratory.

Special Variety - Trapiche Emerald

Trapiche emeralds are usually found in Colombia. Recently the authors received six emeralds reportedly from Swat Valley, Pakistan, polished as double-sided wafers, retaining their original hexagonal crystal habit and exhibiting a trapiche-like pattern.
These samples weighed from 0.38 to 0.83 ct, with a refractive index of 1.588–1.599 and a birefringence of 0.009–0.011.

Generally, these trapiche emeralds were composed of four parts from rim to core: a green rim, a light green area, six arms, and a colorless core, as illustrated. The rims had a highly saturated green color, and most were relatively clean except for several fractures and tiny fluid inclusions. The rims ranged from approximately 1 to 2 mm wide. Although the boundary between the green rim and the light area was not very sharp, a hexagonal boundary was visible. Six black arms spread in a hexagonal symmetric pattern, with each arm perpendicular to the hexagonal side. The colorless core usually had a hexagonal shape.

Microscopic observation revealed that every arm contained many minute black platy inclusions. These small particles appeared dark under transmitted light , while they showed bright metallic luster under reflected light. Micro - Raman analyses  identified these inclusions as magnetite. Peaks at 662 and 545 cm–1 were consistent with two main peaks of magnetite, according to the RRUFF online database (rruff.info), while peaks at 683 and 400 cm–1 may be assigned to the emerald host.

Chemical analysis by energy - dispersive X - ray fluorescence (EDXRF) on the sample shown in figure 19 revealed an iron content of 20,860 ppm (n = 3) in the light green area and 17,000 ppm (n = 3) in the rim. The difference in iron content may be due to the inclusions, since magnetite (Fe₃O₄) is mainly composed of iron and oxygen.

They range from 0.83 to 0.38 ct from left to right, with a thickness of about 1.51 to 2.08 mm. Photo by Kaiyin Deng.

The trapiche emeralds from Pakistan were mainly composed of four parts: a green rim, a light green area, six arms, and a nearly colorless core as illustrated in figure A. These arms appear dark under transmitted light (B) and show bright metallic luster under reflected light (C); field of view 8.48 mm. Illustration and photos by Yujie Gao.

Raman analysis identified these inclusions as magnetite. Peaks at 662 and 545 cm⁻¹ agree with the two main peaks of magnetite, according to the RRUFF database, while peaks at 683 and 400 cm⁻¹ may be assigned to the emerald host.

Application of Swat Emeralds in the Luxury Goods Market

As one of the five most precious gemstones, emeralds have always been sought - after by royalty in Western society. There are many legendary pieces of jewelry in history, such as the Catherine Crown, Empress Josephine's emerald necklace, the Delhi Durbar necklace and short - necklace, all of which show people's preference for emeralds. The vivid and dark green Swat emeralds usually have a small grain size, and most faceted finished products are less than 1 carat. With the continuous combination of jewelry and watchmaking techniques, inspired by the natural beauty of emeralds, European luxury watch and jewelry companies have purchased a large number of small - sized emeralds from Pakistan and used them in watchmaking. After meticulous carving, they give people a strong visual impact.

Report of Swat Pakistan emeralds - sample

Acknowledgements:
Thanks to Mr. Hayat from Pakistan for providing the mine - area pictures, and thanks to Kaiyin Deng and Yizhi Zhao for taking some of the pictures.

Authors of this article: Xueying Sun, Yujie Gao