Matryoshka (diamond)

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The Matryoshka diamond ( Russian Алмаз-матрёшка ) is a greenish diamond , around 800 million years old . It is the only diamond found so far with a - movably mounted - second diamond in the middle.

Find and first description

The greenish diamond was in October 2019 from employees of ALROSA in Nyurba - open pit near the Vilyuy River , Sacha , Siberia found in the sort. Here are since 2001 in a kimberlite - chimney annually about 5 million carats promoted (100 kg) diamonds.

The thick-paneled, truncated, windowed-appearing octahedron has a total weight of 0.62 ct (carat) corresponding to 0.124 g with dimensions of 4.8 × 4.9 × 2.8 mm. A “main window” provides a clear view of the inner diamond. The volume of the cavity is 6 mm³. The flattened, tabular inner diamond with a hexagonal outline has a volume of 1.6 mm³ by 0.02 carats (0.004 g) and a size of 1.9 × 2.1 × 0.6 mm. It is the only find of its kind. The name was derived from the Russian, egg-shaped doll Matryoshka , due to the “diamond nesting” of two diamonds .

Further investigation and development hypotheses

The diamond was examined by ALROSA using Raman and infrared spectroscopy as well as X-ray microtomography. Based on the investigations, the scientists concluded that the inner diamond was formed first. The outer diamond was then formed around the inner one, discussing two hypotheses . Either a shell mineral was placed around the diamond, which was later dissolved, or a porous, polycrystalline diamond structure formed inside the diamond due to very rapid growth , which was later dissolved by the shell formation.

The results of a further investigation by the Gemological Institute of America (GIA) were published in 2020. The analysis carried out by the GIA showed for the first time two 200 μm large channels at the corners, which connect the inner cavity with the outside. The stone was determined to be Type Ia diamond by absorption spectroscopy . The inner diamond has almost the same composition as the outer one. Therefore, a new, third theory for the formation of the diamond was discussed after the internal cavity was examined by μ-CT. According to this, the diamond was formed as a single, filled diamond in the earth's interior under high pressure. Due to chemical heterogeneity or micro-inclusions, around 0.11 ct of the diamond dissolved through interaction with melts / liquids and found its way to the surface through the channels. The leftover material was already inactive against interactions. In the end, liquids with radioactive elements provided the green color and radiation spots. It is known that diamonds can be partially dissolved and reshaped during their formation in the earth's mantle through interaction with melts or liquids. A similar development history has also been described for a green diamond in a colorless diamond, the opening being larger here.

On the basis of these investigations, the volume of the diamonds and the cavity were determined by calculation. The outer diamond has a volume of 33.16 mm³ (0.58 ct). The inner diamond has a volume of 1.51 mm³ (0.03 ct). The total weight is 0.61 ct. The volume of the cavity is 5.99 mm³, which corresponds to 0.11 ct. The total weight of the original diamond was 0.72 ct.

Whereabouts

According to company information, the matryoshka diamond remains in the company collection, along with other curious diamonds.

Web links

literature

  • Wuyi Wang, Emiko Yazawa, Stephanie Persaud, Elina Myagkaya, Ulrika D'Haenens-Johansson, Thomas M. Moses: Formation of the “Matryoshka” Diamond from Siberia . In: Gemological Institute of America (Ed.): Gems & Gemology . tape 56 , no. 1 . New York 2020, p. 127-129 (English).

Individual evidence

  1. ↑ a b c d e Wuyi Wang, Emiko Yazawa, Stephanie Persaud, Elina Myagkaya, Ulrika D'Haenens-Johansson, Thomas M. Moses: Formation of the “Matryoshka” Diamond from Siberia . In: Gems & Gemology . tape 56 , no. 1 . New York 2020, p. 127-129 (English).
  2. ↑ One is in the other - Matryoshka diamond found in Siberia. Bild.de , October 6, 2019, accessed on October 7, 2020 .
  3. ↑ a b c d e Noble Russian "Matryoshka": The diamond in a diamond. Lapis, accessed October 7, 2020 .
  4. ↑ Alrosa finds Matryoshka-style stone, the first in diamond mining history. October 4, 2019, accessed October 6, 2020 .
  5. ↑ a b Matryoshka diamond found in Yakutia. ALROSA, accessed October 6, 2020 .
  6. ↑ a b ALROSA publishes video of unique diamond «matryoshka». News.ru, October 4, 2019, accessed October 6, 2020 .
  7. ↑ Miner Alrosa Finds Russian Doll-Type Diamond With Another Gem Inside. Bloomberg News , October 4, 2020, accessed October 6, 2020 .
  8. ↑ Stephen Morisseau: GIA Researchers Reveal the Secrets to Diamond-in-a-Diamond Mystery. Gemological Institute of America (GIA), January 13, 2020, accessed October 7, 2020 .
  9. ^ Nathan Renfro, John I. Koivula: Diamond with Mobile Green Diamond Inclusion . In: Gems & Gemology . tape 56 , no. 1 , 2020, p. 141 .