Aggregate of Connellite and Brochantite forming a very characteristic coating, with botryoidal development and undulating surfaces that generate irregular reliefs and shallow cavities. Connellite appears with more intense bluish-green tones, concentrated in lower areas and in small cavities, while Brochantite dominates in lighter green tones, with a more matte aspect and more extensively covering the matrix. The chromatic contrast between both species, together with the complexity of the surface, provides great visual richness to the whole.
Worth noting is the rarity of this association and the fact that it comes from a classic locality. An uncommon specimen.
Polberro Mines is a small historic mine located in the Saint Agnes area, within one of Cornwall’s classic mining districts. It belongs to the network of workings developed along the St Agnes vein system, known for tin and copper mineralization and for a wide variety of well-crystallized secondary species.
Geologically, the mineralization is related to hydrothermal systems associated with the Hercynian granitic intrusions of Cornwall. The veins, typically trending E–W, are hosted in metasedimentary and granitic rocks, with a typical paragenesis including Cassiterite, Chalcopyrite and other sulfides, accompanied by secondary minerals formed in oxidation zones.
Polberro Mines, Saint Agnes, Saint Agnes mining district, Cornwall England / United Kingdom (±1986)
Specimen size: 9.5 × 5.8 × 2.3 cm = 3.74” × 2.28” × 0.91”
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