TFF12XXX: Specimen in which the excellent state of preservation of the Pyrite and Calcite stands out, both with good luster and without visible damage. The Pyrite forms aggregates of crystals partially covered by white Calcite crystals. On the surface of the Pyrite, small Sphalerite crystals are present, adding interest to the specimen.

From a geological point of view, this type of association is characteristic of sedimentary and diagenetic environments in Jurassic limestones, where fluids rich in iron, sulfur and, sometimes, zinc precipitate sulfides such as Pyrite and Sphalerite, later accompanied by carbonates such as Calcite.

Hampstead Quarry is located in the Cotswolds area, known for its outcrops of Jurassic limestones (mainly Lower and Middle), with typical oolitic facies. These limestones may show cavities and fractures where secondary mineralizations develop, mainly carbonates and sulphur and iron oxides, within a shallow marine sedimentary context.
Hampstead Quarry, Hampstead, Cotswold District, Gloucestershire  England / United Kingdom

Specimen size: 6.8 × 5.7 × 2.4 cm = 2.68” × 2.24” × 0.94”

Main crystal size: 1.5 × 0.9 cm = 0.59” × 0.35”