Fluorite - Color-Changing Green-Blue

This exceptional fluorite specimen originates from the Cousin Jack Pocket, a notable discovery made in spring 2022 at the legendary Rogerley Mine, Weardale, County Durham, England. This pocket has produced some of the finest fluorite crystals ever recovered from the locality, distinguished by their remarkable optical behavior, clarity, and refined crystal form. The specimen is particularly notable for featuring a single, well-defined cubic fluorite crystal prominently positioned on the matrix—an arrangement that is exceptionally rare for the Rogerley Mine, where clusters and tightly intergrown crystals are far more typical. The isolated cube is aesthetically well-balanced, rising cleanly from the contrasting dark matrix and drawing immediate visual focus. Surrounding penetration-twinned and interlocking cubes provide context and depth without detracting from the dominance of the primary crystal. Transparency is notably high for English fluorite, allowing for rich internal color saturation and dimensionality. Under standard indoor lighting, the crystals display a deep, saturated green. When viewed in natural daylight, they undergo a dramatic transformation to blue-violet, a hallmark characteristic of elite Rogerley material. Under ultraviolet light, the specimen fluoresces an intensely vivid ultramarine, creating a striking and highly collectible optical display. The combination of a rare isolated cubic crystal, strong daylight color change, vivid UV fluorescence, and precise compositional balance elevates this piece to a top-tier modern Rogerley fluorite, suitable for advanced private collections or institutional display.