Quartz after Melanophlogite

Unknown Owner

A plate of banded blue quartz, the top covered by lustrous blue quartz replacing previous crystals of melanophlogite measuring to 0.3 cm in size. In great condition. A choice antique specimen from this well-known European locality. The specimen comes with an antique label as shown at the end of the video and dates to the early 20th century.The Trestia locality, situated in the Maramures County of northern Romania, is a world-famous site for unique chalcedony and quartz pseudomorphs. Geologically, these specimens are found within a highly weathered, altered volcanic environment where silica-rich fluids filled cavities in the host rock. Historically, the sharp, cubic crystals found here were long believed to be quartz replacements after fluorite due to their distinct geometric shape. However, modern mineralogical research and crystallographic analysis have determined that the original mineral was actually melanophlogite, a rare silica clathrate that forms cubic or rounded crystals at low temperatures. These pseudomorphs are highly prized by collectors for their striking blue or bluish-grey color and their distinctive "bubbly" or micro-crystalline surface texture. The transformation from unstable melanophlogite to stable quartz and chalcedony has preserved the sharp cubic morphology of the precursor, making Trestia the premier global locality for this specific mineralogical oddity.