Skarn geology
Daye is a textbook skarn deposit: a granitic intrusion baked the surrounding Triassic limestone, driving hot mineral-rich fluids into the contact zone. Iron (magnetite), copper (chalcopyrite, bornite), and pyrite precipitated as the primary ore. Open vugs in the contact zone provided space for spectacular calcite, dolomite, and pyrite crystals.
The signature look
Bright golden pyrite cubes, often with druzy quartz dustings, on creamy or grey dolomite matrix. Calcite scalenohedrons grow on top. Many pyrite plates show striking surface iridescence — purple, blue, and gold reflections from a thin sulfide oxidation layer that develops naturally underground. Iridescent Daye specimens are among the most distinctive in modern collecting.
Other species
Chalcopyrite (metallic golden cubes with sometimes-flashy iridescence), bornite (peacock-ore iridescence), arsenopyrite, sphalerite, magnetite. The associated dolomite matrix often has subtle pink color from manganese substitution. Specimens with calcite + iridescent pyrite + dolomite matrix are the locality's flagship combo.