Yellow crystal aggregates of the very rare Pb-Fe silicate Langban mineral jagoite from the type and only one of the two known localities worldwide, both in Sweden, in a small piece of matrix. Ex Vandenbroucke Museum collection from Waregem, Belgium. — Photo: David Hospital · CC BY 4.0
Jagoite
A rare yellow-green hexagonal lead silicate published in 1957.
Intro adapted from Wikipedia (CC BY-SA).
Jagoite is an IMA-recognized mineral species in the silicate class, with the chemical formula Pb₁₈Fe³⁺₄[Si₄(Si,Fe³⁺)₆][Pb₄Si₁₆(Si,Fe)₄]O₈₂Cl₆.
It crystallizes in the hexagonal crystal system (space group P-62c).
Key properties: Mohs hardness 3; specific gravity 5.43; Yellow streak; Vitreous, shining on cleavages luster; optically uniaxial.
IMA symbol Jg, grandfathered status — known before the IMA’s founding, named in 1957.
Found in hematite ore in a metamorphosed Fe{Mn orebody.
It is found associated with Melanotekite, quartz.
The name refers to John Bernard Jago Trelawney (1909–2001), American mineral collector of Palo Alto, California, USA, and benefactor of mineral collections in the USA.