THE FUMAROLE-SULFATE ORIGIN OPALITES AS A MINE-DEPOSITE OF NEW TYPE AND A HIGH TECHNOLOGICAL BASE FOR SILICATE PRODUCTION. Proceedings of the YSU C: Geological and Geographical Sciences, Yerevan, Armenia, v. 35, n. 3 (196), p. 143–148, 2025. DOI: 10.46991/PYSUC.2001.35.3.143. Disponível em: https://journals.ysu.am/index.php/proceedings-geol-geogr/article/view/vol35_no3_2001_pp143-148. Acesso em: 22 jan. 2026.