Tsavorite: The new noble green gemstone

introduction

Starting today, the "Treasures of the Museum" column will launch a series of precious stones. The first one I will introduce to you is a tsavorite, which is also the treasure of the China Geological Museum.

The treasure of the town

Tsavorite, 144.45ct

Collected by China Geological Museum

Green grossular garnet rough stone, collected in China Geological Museum

Tsavorite, also known as Tsavorite (USA) or Tsavolite (Europe), is a gem-grade green vanadium and/or chromium-containing grossular garnet, a member of the garnet family. Although tsavorite has a humble origin and does not have a long history and culture, it has frequently appeared in the series of major high-end jewelry brands as soon as it was launched, thanks to its superb appearance. It can be said to be a new noble among green gemstones. Tsavorite is produced in Africa. Because of its bright green color and dazzling brilliance, it can be compared with the best emeralds, and is also known as the "King of African Gems".

At the end of 2011, the China Geological Museum collected a 144.45ct (1 ct = 0.2 g) tsavorite from East Africa. It is oval-faceted, emerald green, and extremely transparent. Its size is 35.21mm×29.45mm×18.61mm, ranking among the best in the world. The collection was cut and polished in Ida-Oberstein, Germany, which is famous for its exquisite craftsmanship, and the test report was issued by the Gübelin Gem Lab in Switzerland. It is the largest tsavorite ever tested by the laboratory.

Since the formation conditions of tsavorite are very harsh, only the gem-grade green grossular garnet variants colored by the right amount of vanadium and/or chromium ions can be called tsavorite, and its particle size is usually very small. It is very rare to be able to cut into 2~3ct, and those above 5ct can reach collection grade. This huge tsavorite collected by the China Geological Museum is of treasure grade and extremely rare and precious.

Worth a fortune

Tiffany rings Boucheron rings

(The green gemstone is tsavorite, the picture comes from the Internet http://www.xbiao.com/)

Tsavorite is emerald green, hard, and rare, with a price far higher than other varieties of garnet. Soon after its release, it became a high-end gemstone and the second most sought-after green gemstone after emerald. Tsavorite entered the international jewelry market because of Tiffany. It not only frequently appears in the company's annual high-end jewelry "Blue Book", but is also favored by first-tier jewelry brands such as Boucheron, Chopard, and Harry Winston, and even created amazing results at Sotheby's auctions.

Identification features

Identification Characteristics of Tsavorite and Its Major Similar Gems

Tsavorite has varying shades of green and is easily confused with natural green gemstones such as emerald, chrome diopside, green tourmaline, and peridot. It is identified through polarization, pleochroism, refractive index, density, and inclusion characteristics.

Origin Distribution

Green Grossular Rough Stone

Collected by China Geological Museum

Tsavorite is mainly produced in East Africa. Currently, most of the economically significant tsavorite is produced in Tanzania, Kenya, Madagascar and Pakistan. The particles are usually small, and large particles are extremely rare. In addition, other countries and regions also produce a small amount of tsavorite, such as Afghanistan, Slovakia, Myanmar, Canada, Afghanistan, France, Australia, Zimbabwe and Mexico. Small particles (2~3mm, a few up to 5~8mm) of tsavorite crystals are also produced in Litang, Sichuan, my country.

References

[1] Lü Linsu, Zhang Yong, Gao Xinrui, Lu Taijin, Peng Yanju, Shen Meidong, Chen Hua. 2013. Identification and evaluation of Tsavostone. Jewelry and Technology (Proceedings of the China Jewelry Academic Exchange Conference), 86-90.

[2] Peng Yanju, Lü Linsu, Mao Bing. 2013. Gemological characteristics and distribution of tsavosite. Geological Review, 59(Suppl): 333~334.

[3] Gao Xinrui, Lü Linsu, Zhang Wei. 2013. Gemological characteristics and quality evaluation of Tsavostone in the collection of China Geological Museum. Geological Review, 59(Suppl): 485~486.

[4] Lü Linsu, Mao Bing, He Xuemei. 2014. Current status of mineralogy and geochemistry of East African chrome vanadium grossular garnet (tsavostone). Journal of Gems and Gemology, (4): 1-13.

[5] Lü Linsu, Peng Yanju, Li Hongbo, Zhou Zhenhua, Mao Bing, Gao Xinrui, Yang Senlin. 2015. Discussion on the genetic model of gem-grade chrome-vanadium grossular garnet (tsavoite) deposits in East Africa. Mineral Deposits, 34(2): 404-422.

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Author: Peng Yanju Planner: Zhou Xiangke

Typesetting: Wu Zhaohui

Focus on natural science

Approaching natural resources

Source: Natural Science