Tantalaeschynite-(Ce)

tantalaeschynite-(Ce)

titanite

fluorcalciomicrolite

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Formula: Ce(TiTa)O₆
Valence: Ce³⁺(Ti⁴⁺Ta⁵⁺)O₆
Oxide of cerium, titanium and tantalum, aeschynite group
Crystal system: Orthorhombic
Specific gravity: 6.88 calculated for the empirical formula
Hardness: 5½
Colour: Yellowish orange
Environments

Pegmatites

Tantaleaschynite-(Ce) is a new mineral, approved in 2023 and to date (October 2026) reported only from the type locality.

Localities

At the type locality, Huangshan Nb-Ta deposit, Lingshan complex, Hengfeng County, Shangrao, Jiangxi, China, tantaleaschynite-(Ce) was discovered at the border of a pegmatite dike, and it occurs as subhedral or anhedral granular, tabular crystals and radiating clusters, 10 to 50 μm in size. It is paragenetically associated with Ta-rich titanite and fluorcalciomicrolite. Tantaleaschynite-(Ce) is translucent to opaque and yellowish orange in colour in thin section, with conchoidal fracture and resinous lustre. It co-occurs with other Ta-rich minerals in a narrow zone adjacent to the blocky K-feldspar unit within the Huangshan Ta-rich pegmatite.
There is a sharp, localized Ta enrichment observed in this boundary layer; the presence of tantalaeschynite-(Ce), together with widespread Ta-metasomatic minerals, underscores the critical role of this boundary layer in the petrogenesis of highly evolved pegmatites at Huangshan (AM 111.10.1576-1592).

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