Anglesite, Cerussite, Gypsum, Langite, Malachite, and Posnjakite: New Occurrences in the Calabria Region (Southern Italy)

Abstract

This study undertook the mineralogical and chemical analysis of anglesite (PbSO4), cerussite (PbCO3), gypsum (CaSO4∙2H2O), langite (Cu4(SO4)(OH)6∙2H2O), malachite (Cu2CO3(OH)2), and posnjakite (Cu4(SO4)(OH)6·H2O) detected for the first time in the abandoned Mastricarro Barite Mine (Catanzaro, Calabria, southern Italy). Geological conditions make this one of the few well-preserved, partly accessible mines in the Calabria region. Numerous mineralogical species, some beautifully crystallized, have been discovered among the alteration products of the sulfides present within the barite veins. The newly identified crystals occur as secondary minerals in the oxidized portions of deposits originally containing lead and copper sulfides; they are widely distributed and are almost always detected as microcrystals. The anglesite, cerussite, gypsum, langite, malachite, and posnjakite crystals were identified and characterized using optical microscopy (OM), micro-Raman spectroscopy (µR), and scanning electron microscopy, combined with energy dispersive spectrometry (SEM/EDS). The new mineral occurrences can be useful for scientific and didactic purposes; further, for langite, malachite, and posnjakite crystals, new Raman bands, which have not been mentioned before in the literature, were identified.

Determining the Structural Properties and Vibrational Modes of Annealed Lead Composite Material Deposit

“…[ 19 ] This implies that the sample can be classified as Pb‐based particles with other elements (e.g., Zn and S). Additionally, EDX analysis from a recent study [ 20 ] on anglesite (PbSO 4 ) also reported some trace of copper impurities (5 wt%) detected on the crystal surface. Similarly, in the present study, results obtained from the EDX analysis of the annealed Pb composite material confirmed the existence of Zn, carbon (C), silicon (Si), S, and oxygen (O) in the material, while Pb appeared to be the primary constituent with reference to its weight percentage composition compared to other elements.…”

“…A recent study on PbSO 4 crystals indicates that they appear euhedral when observed through SEM and are usually snuggled in cavities surrounded by galena. [20] To complement the results obtained from EDX analysis, further investigation was conducted to identify the compounds present in the composite using Raman spectroscopy. Good Raman spectra were obtained using a WiTec alpha 300RA þ Confocal Raman Microscope to analyze the sample.…”

“…A recent study on PbSO 4 crystals indicates that they appear euhedral when observed through SEM and are usually snuggled in cavities surrounded by galena. [ 20 ]…”