IR Naturally Occurring Asbestos (NOA) PCOM RD-UV-Vis spectroscopy SEM Southern Italy XRD aggregates antigorite asbestiform and fibrous minerals asbestos asbestos' minerals asbestos-containing materials chrysotile cleavage fragments edenite environmental monitoring fibrous habitus grinding test health hazard image analysis lizardite characterization melting process morphology naturally occurring asbestos polymorphs recycling rhino white marble of Namibia serpentine varieties serpentinite soil