The Quartzofeldspathic Fulgurite of Bustaviejo (Madrid): Cathodoluminescence and Raman Emission

We discover and study a new quartzofeldspathic fulgurite, sized 12 cm in diameter in the main branch, of Bustarviejo (Madrid, Spain). Here we characterize fulgurite aliquots by Electron Probe Microanalysis (EPMA), Environmental Scanning Electron Microscopy with a X¿ray Dispersive Spectrometry and cathodoluminescence probes (ESEM¿EDS¿CL), in situ high¿temperature X¿ray diffraction (HTXRD), Hyperspectral Raman Microscopy (Raman) and Thermoluminescence (TL). The fulgurite body was formed by lightning strike fusion on arkose sand during a fast process of volatilization and extreme reducing conditions at temperatures in excess of 2000 K. The fulgurite is composed of schocked quartz, neo¿formed cristobalite, native Si¿Fe¿Al alloys and aluminum¿silicate glass with spherical cavities. Both, the hyperspectral CL and Raman mappings highlight the cristobalite rim of the schocked quartz grains. The phase transition quartz¿cristobalite preserves and enlarges the spectral CL structure, conversely the melting process forming glass phase destroys some CL defects remaining other structural centers, e.g., oxygen efficient centers, responsible of the 300 and 520 nm CL emission bands. In addition we also identify a nice description on quartzofeld¿spathic fulgurite, labelled mazintarincan, in the medievaeal book, The Lapidary of King Alfonso X The Learned, written in the XII Century, at 1250Peer Reviewe