Fluorite - Diana Maria Mine, England

Locality: Diana Maria Mine, Rogerley Quarry, Weardale, County Durham, England, UK
Dimensions: 77*78*71mm/509g

Since underground mining began in 2017, the Diana Maria Mine has consistently produced world-class fluorite specimens admired by collectors worldwide. The mine exploits the Sutcliffe Vein, an extension of the famous Rogerley Quarry to the west. Within this remarkable deposit, individually named pockets—including Queen of Green, Green Hill, Naughty Gnome, and Hidden Forest—have each yielded fluorite specimens with their own distinctive character, establishing Diana Maria as one of the most celebrated active specimen localities in the United Kingdom.

This specimen displays an elegant cluster of sharp cubic crystals, with colour transitioning from rich emerald green to translucent mint green. The crystals are firmly seated on a substantial dark grey matrix, creating a striking contrast that enhances their brilliance. Mirror-like crystal faces reveal delicate internal colour zoning, while changing light brings out remarkable depth and dimension within each individual cube.

One of the most celebrated characteristics of fluorite from the Diana Maria Mine is its remarkable daylight colour-change effect. Under indoor artificial lighting, the crystals display a saturated emerald-green hue. When viewed in natural daylight, the colour shifts noticeably toward blue-green and even indigo tones. Under long-wave ultraviolet (LWUV) illumination, the crystals emit a vivid blue-white fluorescence. Indeed, the scientific term "fluorescence" itself derives from fluorspar, the historical name for fluorite.

Scientific studies suggest that this extraordinary green colour is primarily caused by structural defects within the fluorite crystal lattice rather than by simple chemical impurities. This phenomenon not only creates the mine's distinctive visual appeal but also gives these specimens considerable mineralogical and scientific significance.