VANADINITE WITH CALCITE

ABOUT THE SPECIMEN It takes something special to stand out among the tons and tons of vanadinite from the extensive workings in Mibladen, this here is one such piece: a simply stunning, humongous cluster on matrix with a coating of calcite druze. The coverage goes over almost the entire top, save for a small patch where sheets of barite are visible. Many of the vanadinite crystals are blood red all the way through, many have beige color on the sides, and some have an almost black coloration. The drusy calcite could easily be removed, though no guarantees on how the underlying crystals would look afterwards. Personally, I like the contrast and sparking luster that this epitaxial layer adds to the piece. It's no exaggeration to say that there are thousands of vanadinites present here, and just the size of the specimen alone makes it stand out in any collection.   MORE INFO Mibladen is a stratiform Pb-Ba deposit hosted in Lower Jurassic (Liassic) limestones and dolomites of the High Atlas approximately 25 km northeast of Midelt, mined commercially for lead by French operators from the mid-1930s until closure in 1983. Vanadinite formed secondarily as the arid climate of the Atlas facilitated oxidation of galena without the interference of significant rainfall; vanadium sourced from the surrounding sedimentary sequence combined with lead in the oxidation zone to precipitate the hexagonal lead chlorovanadate. Crystals are typically thick tabular to prismatic hexagonal prisms, predominantly deep red to orange-red, with color zoning occasionally visible as a saturated orange core transitioning to deeper red toward the prism terminations; a rare subset displays skeletal growth on prism faces producing a translucent cat's-eye effect when viewed down the c-axis. Most specimens are floaters or occur on tan baryte and limonite matrix. Since the industrial closure, the deposit has been worked periodically by small-scale Moroccan miners sinking shallow shafts from surface - a 2019 discovery sparked a significant mining rush producing new material after years of the market depending entirely on old stock. Praszkier's 2013 Mineralogical Record account remains the definitive published treatment of the locality.