Recently, the authors investigated a set of three colorless quartz samples, each exhibiting distinctive black fibrous inclusions. Microscopic observation revealed that the metallic opaque crystals were often arranged in parallel or radial formations (see above). These inclusions were identified by Raman spectroscopy as the rare mineral mannardite (Ba(Ti4+6V3+2)O16). Mannardite is a member of the cryptomelane group (hollandite) and is found in Russia, Northwest Kazakhstan, and South China, with these inclusions typically ranging from 15 to 50 μm in width.
This discovery offers new insights into low-temperature hydrothermal mineralization processes, as the coexistence of mannardite with quartz suggests formation under specific redox conditions (X. Fu et al., “Mineralogy and trace element geochemistry of the early Cambrian black shale-hosted Zhongcun vanadium deposit, southern Qinling, China,” Ore Geology Reviews, Vol. 155, 2023, article no. 105371). These findings contribute to understanding vanadium-rich mineral paragenesis in quartz-bearing systems and highlight Raman spectroscopy’s critical role in nondestructive mineral identification at the micrometer scale.
Liyan He is affiliated with the Guangdong Gemstones & Precious Metals Testing Center in Guangzhou, China. Wingtak Lui is affiliated with Min De Minerals & Gem Research Co., Ltd. in Nanjing, China.
Recently, the authors investigated a set of three colorless quartz samples, each exhibiting distinctive black fibrous inclusions. Microscopic observation revealed that the metallic opaque crystals were often arranged in parallel or radial formations (see above). These inclusions were identified by Raman spectroscopy as the rare mineral mannardite (Ba(Ti4+6V3+2)O16). Mannardite is a member of the cryptomelane group (hollandite) and is found in Russia, Northwest Kazakhstan, and South China, with these inclusions typically ranging from 15 to 50 μm in width.
This discovery offers new insights into low-temperature hydrothermal mineralization processes, as the coexistence of mannardite with quartz suggests formation under specific redox conditions (X. Fu et al., “Mineralogy and trace element geochemistry of the early Cambrian black shale-hosted Zhongcun vanadium deposit, southern Qinling, China,” Ore Geology Reviews, Vol. 155, 2023, article no. 105371). These findings contribute to understanding vanadium-rich mineral paragenesis in quartz-bearing systems and highlight Raman spectroscopy’s critical role in nondestructive mineral identification at the micrometer scale.
Liyan He is affiliated with the Guangdong Gemstones & Precious Metals Testing Center in Guangzhou, China. Wingtak Lui is affiliated with Min De Minerals & Gem Research Co., Ltd. in Nanjing, China.
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