European Journal of Mineralogy
European Journal of Mineralogy
European Journal of Mineralogy
Articles | Volume 38, issue 3
Articles | Volume 38, issue 3
https://doi.org/10.5194/ejm-38-305-2026
© Author(s) 2026. This work is distributed under
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/ejm-38-305-2026
© Author(s) 2026. This work is distributed under
the Creative Commons Attribution 4.0 License.
Articles | Volume 38, issue 3
Research article
 | 
22 May 2026
Research article |  | 22 May 2026

Formation of black opal in the pegmatites from Volyn (Ukraine) – an example for interaction of silica with organic matter

Gerhard Franz, Vladimir Khomenko, Vsevolod Chornousenko, Armin Zeh, Ferry Schiperski, Simon Gouzy, Ulrich Gernert, and Jörg Nissen

Viewed

Total article views: 130 (including HTML, PDF, and XML)
HTML PDF XML Total BibTeX EndNote
91 32 7 130 6 6
  • HTML: 91
  • PDF: 32
  • XML: 7
  • Total: 130
  • BibTeX: 6
  • EndNote: 6
Views and downloads (calculated since 22 May 2026)
Cumulative views and downloads (calculated since 22 May 2026)

Viewed (geographical distribution)

Total article views: 124 (including HTML, PDF, and XML) Thereof 124 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
1
 
 
 
 
Latest update: 13 Jun 2026
Download
Short summary
Black opal, a rare amorphous SiO2 variety, results from the interaction of silica with organic matter and therefore hints at traces of life, including the early Earth and Mars. The Volyn occurrence is one of the few examples of black opal worldwide and is the unique case of a pegmatitic occurrence in a granite; its age is at least 200 Ma. The structure consists of micrometer-large sphere-like arrangements of nano-sized grains and shows shape relicts of fossils, known from Volyn as "kerite".
Read more
Share