The SEM also generates an electron beam that interacts with the atoms in the sample and is capable of detecting the characteristic X-rays of the atoms that compose it. However, it uses an energy-dispersive spectroscopy (EDS) system - which has lower resolution than the WDS system, but is faster, making it ideal for analyses of abundant elements and screening analyses. In addition, the SEM is designed to perform imaging and is equipped with backscattered electron (BSE) and secondary electron (SE) detectors. BSE images provide indirect compositional information, while SE images provide topographic information of the sample.

Application: In Geosciences, it is widely used in petrographic analyses and imaging of fossils and minerals. Its application, however, goes far beyond that, being widely used in imaging of electronic micro components, glass and ceramic materials, metal alloys, and organic structures.

XRD generates X-rays through a type of lamp, where a high electric current induces the release of electrons from a filament and, through the application of an electric potential difference, these electrons are directed against a metallic target (usually copper or molybdenum), generating X-rays with energy characteristic of these targets. The X-ray photons are collimated and directed to the pulverized sample, where they interact with it and diffract in its crystalline lattice. The detector moves around the sample in predetermined angular steps, measuring the intensity of the photons diffracted by the sample. The result is a diffractogram, a graph that shows intensity in relation to angular position. Each crystalline arrangement has a unique diffractogram, which is a kind of fingerprint of the material.

Application: In Geosciences, it is widely used for characterizing the mineral composition of rocks and characterizing minerals, including clay minerals. It has broad application in the chemical and pharmaceutical industries, as well as being a powerful tool in forensic and ceramic material analyses.

XRF uses an X-ray beam (produced similarly to XRD) to induce the emission of characteristic X-rays in the sample. These characteristic X-rays are then analysed using systems similar to WDS and EDS.

Application: It is a fundamental technique for analysing the overall composition of a rock, soil, or ore, for example. It can also be applied in the analysis of liquid and pasty materials, such as water, food, and lubricating oils. In addition, it has the ability to generate fluorescence maps, which show variations in the concentrations of key elements in the sample, which is important in the analysis of biological materials, metal alloys, and cements, for example.

Raman spectroscopy is based on the inelastic scattering of visible light photons as they interact with the sample. That is, when a monochromatic laser beam (with a single wavelength) hits the sample, most of the photons from that laser will either be scattered elastically (reflected) or absorbed by the material (converted into heat, for example). But a small fraction of these photons interacts with the sample at specific frequencies (vibrational modes) and return to the detector with a small variation in their energy. The energy and intensity of these photons are measured, and the result is a Raman spectrum, a signature of the sample.

Application: an excellent analytical tool for gemological materials and historical artifacts, as no sample preparation is required (beyond a light surface cleaning). It is widely used in jewelry analysis, being fundamental in the authentication of minerals - such as diamonds, sapphires and emeralds -, as well as being very useful in forensic and biological material analyses.

FTIR technique is based on generating an interference spectrum (in the infrared range) between a direct beam and a beam that interacts with the sample. The result of this process (the interferogram) is mathematically processed using the Fourier transform to generate a spectrum. The FTIR spectrum shows which wavelengths are absorbed at what intensity by the sample, and this can be translated as which energies are being used by the sample to cause vibrations in its molecules. Each wavelength range corresponds to a vibrational mode, and in this way, it is possible to model the structure and (to a certain degree) the composition of the material.

Application: widely used in the analysis of clay minerals, but it is a powerful tool for analysing mineral inclusions, fossils, pharmaceuticals, and liquid and gaseous materials, such as wine, milk, honey, and fuels.

UV-Vis spectroscopy, like FTIR, is a vibrational spectroscopy, that is, it analyses how the sample interacts with a specific wavelength range (in this case, ultraviolet and visible).

Application: widely used in the analysis of liquid and gaseous materials, such as beverages, fuels and lubricating oils, and it is also a very interesting tool in the characterization of gemological materials.

An optical microscope with polarizing lenses is used to identify minerals in thin sections, as well as to define textures and microscopic structures of rocks.

Application: in Geosciences, optical microscopy is the fundamental analytical technique. Other materials such as metallic alloys, cements and ceramic materials can also be analysed by this technique.