Is it possible to use the diagnostic tools of modern medicine to know the 'state of health' of our planet? The answer is given by the researchers of the X-Ray Diffractometry Laboratory of the INGV Vesuvius Observatory.
In fact, here scientists use X-rays to "screen" the rocks that make up our planet and obtain from their analysis all the mineralogical information they need: from the functioning of the magmatic systems to the reconstruction of the eruptive dynamics, passing through the study of hydrothermal and geothermal alteration processes, but not only.
A versatile Lab that we discovered through the words of its manager, researcher Angela Mormone.
Angela, when was the Laboratory born?
The X-Ray Diffractometry Laboratory, located at the INGV Vesuvius Observatory, was born in October 2012 thanks to the purchase of the X' PERT PRO diffractometer.
How would you explain the X-ray diffractometry technique to a non-expert audience?
Good question! We usually associate X-rays with diagnostic tests… In our laboratory, thanks to the use of the diffractometer, we too carry out a sort of “screening” on powders (sometimes on massive samples), defining their constituents. Unlike a radiograph in which the image obtained is the result of a different absorption of X-rays depending on the tissue crossed, in diffractometry the image obtained is a diffraction spectrum, resulting from the constructive interference of an X-ray with the grating crystalline, an ordered, periodic and three-dimensional scaffolding of the atoms that make up the "skeleton" of the mineral.
The diffraction spectrum is characteristic and unique for the individual mineralogical species, and consists of a series of peaks that vary in position and intensity. The analysis of the position, intensity, width and shape of the peak allows us to obtain the mineralogical information we need.
What tools do you use for your research?
Our Lab, in addition to the X' PERT PRO diffractometer, is equipped with a series of instrumental supports: a “multiple purpose sample stage” to mount massive samples; a heating chamber (HTK1200Anton Paar), which reaches temperatures of 1200°C, for the study of the variations of the structural parameters and of the phase transformations; a binocular microscope for preliminary observation of the sample and manual separation (handpicking) of the mineralogical phases to be analysed; a series of agate mortars, for the micrometric pulverization of the sample; a set of interchangeable sample holders, on which powders can be easily placed.
What are the activities that characterize the work you carry out within the Lab?
The activities carried out in the laboratory are innumerable thanks to the versatility, the acquisition times and the contained costs of the analyses. X-ray diffractometry, in fact, is a non-destructive mineralogical investigation, which allows to identify the minerals that make up a rock (volcanic and non-volcanic), an archaeological find, a cement material (including ceramics), a pharmacological or synthetic product .
Diffractometry, for example, is fundamental in petrology, for the characterization of the mineralogical associations of volcanic rocks, to contribute to studies on the functioning of the magmatic system and on the reconstruction of the eruptive dynamics; it is fundamental for the study of hydrothermal and geothermal weathering processes. The study of mineralogical phases, among other things, is extremely important also in archaeometry; the presence or absence of certain minerals, in fact, is not only indicative of the firing temperature and of the processing techniques of the ceramics and mortars, but provides valid elements for establishing and reconstructing itineraries useful for identifying the origin of the materials used.
Although minerals are widely used in countless fields of applications due to their advantageous characteristics, they do not always play such a benevolent role, just think, for example, of their "complicity” in kidney stones (calcium phosphates, struvite) or their use as fiber-cement compounds (Eternit) or when they contribute to the “dangerous” concentrations in natural deposits (asbestos). In this regard, X-Ray diffractometry can however alleviate the negative effects of the same minerals by contributing to their identification, quantification and characterization to limit damage and facilitate possible remedies.
Last but not least, diffractometric investigations are indispensable for the characterization of extraterrestrial soils and rocks, as demonstrated by the numerous investigations conducted on samples taken during the missions on Mars, contributing to the reconstruction of the history and geological processes of the planet red.