ILVAITE WITH HEBENBERGITE ON CHLORITE

ABOUT THE SPECIMEN All around this specimen are starburst clusters of jet-black ilvaite shooting out of a chlorite-covered matrix. Judging by the felted texture, I'm guessing that chamosite is the chlorite group member present. Light hedenbergite caps off almost all of the ilvaite's terminations, with crystals of colorless calcite and bladed crystals of what appear to be barite rounding out the display. The Huanggang Mines redefined expectations for what to expect with ilvaite, and that's only more true when seeing how it occurs with other mineral species in a manner like this. This piece comes with a custom metal prong base to prop it up, although we prefer how it looks standing on its own. Truly a piece of artwork out of a prolific mineral producing locality!   MORE INFO Huanggang comprises seven interconnected mines exploiting Sn-Fe skarn deposits formed during the Yanshanian orogeny, approximately 165-135 Ma, when granite intrusions metamorphosed Carboniferous limestones during Jurassic-Cretaceous compression. Ilvaite (calcium iron silicate hydroxide) appears as jet-black columnar crystals with wedge-shaped terminations reaching 3-5 cm, typically associated with dark green hedenbergite (calcium iron pyroxene) in radiating sprays or massive forms. Chlorite occurs characteristically in certain ore bodies, particularly No. 3 Mine, forming green platy masses that geothermometry indicates crystallized near 300°C during later mineralization stages. The iron-rich skarn minerals formed through metasomatic replacement processes where silica-rich fluids from cooling granite reacted with iron-bearing carbonate rocks. What makes Huanggang significant is its mineralogical diversity; dealers dubbed it the "New Dalnegorsk" when specimens first appeared around 2010, referencing the famous Russian locality. The finest ilvaite came from 2011 pocket finds including elegant floater crystals, while No. 1 Mine produced darker hedenbergite with garnet, quartz, and fluorite associations. Material initially reached markets mislabeled as "Baotou District" before the true locality became known. Production continues, though the celebrated early finds remain the standard.