Natural Quartz Crystals Research Articles

Investigating the OSL components and the sensitivity changes in a natural quartz crystal showing an intense post-sensitization TL signal

This study aims to investigate the optically stimulated luminescence of quartz grains exhibiting an intense thermoluminescent signal between 250 and 350°C after sensitization with a high dose of gamma radiation and moderate heat treatments. Pellet discs produced with zeroed and sensitized grains were irradiated with test doses ranging from 0.5 to 40 Gy. After sensitization, the OSL signal of the fast component stimulated with blue light increased more than 1000 times. Annealing at 400°C was adopted to erase the residual signal. The sensitivity changes were assessed after various TL and OSL readings. The annealing cycles were responsible for a significant increase in OSL and a 20% reduction in TL signals. The analysis of the residual TL indicated that the traps responsible for the main components of the sensitized peak (280°C) are harder to bleach than those related to the so-called 110, 325, and 375°C peaks. The sensitivity changes and the relationship between OSL and TL signals were explained in terms of a mechanism of competition involving active and deep electron traps. No correlation was observed between the fast OSL component and the 325°C TL peak.

Thermoluminescence of Natural Quartz Grains Beside Huguangyan Maar Lake

In order to study the relationship between the thermoluminescence (TL) properties of natural quartz crystals and the irradiation history, the TL test of quartz particles was carried out on volcanic ash near Huguangyan Maar Lake in Zhanjiang City. The TL glow curve and dose response of quartz were measured. The parameters of TL traps are calculated, and the activation energies corresponding to the TL peaks of 260, 310 and 365 °C of quartz grains are 1.34, 1.44 and 1.51eV, respectively. The peak position of the TL glow curve changes mildly with the increase of irradiation dose of quartz particles, indicating that the energy of a TL trap is not a single value, but an energy distribution; in the range of 355 °C to 375°C, the TL sensitivity changes greatly with the increase of the historical irradiation dose.

Polyvinylidene fluoride, an advanced futuristic smart polymer material: A comprehensive review

AbstractThere was a fast development of various piezoelectric materials in the past two decades due to their numerous applications. Piezoelectric materials made up of natural quartz crystals were used in ultrasonic detectors in the early days. Later, the modern synthetic piezoelectric materials known as ferroelectric ceramics, such as Lead zirconate titanate (PZT), were developed, which were capable of exhibiting piezoelectricity several times greater than natural crystals. Later, the declination of ceramics began as they contained large amounts of lead content, which was considered harmful to both humans and the environment. Finally, a new era in the history of piezoelectric materials boomed with the outbreak of polymer materials. Polyvinylidene fluoride (PVDF) is a piezoelectric polymer material that has drawn the attention of researchers, from the family of fluoropolymers and has paved a new path in the field of polymer science and technology. PVDF has earned the renown of being an excellent piezoelectric material due to its unique and versatile exhibition of piezoelectric and dielectric properties. Furthermore, PVDF can exhibit incredible thermal stability and mechanical strength with flexible processing and low cost compared with the other piezoelectric crystals and ceramics. This comprehensive review mainly focuses on the evolution of piezoelectric materials from crystals to polymers with their advantages and significant drawbacks. Thus, the main objective of this review is to present a detailed description of PVDF concerning its uniqueness as a piezoelectric material and versatile properties, followed by various advanced fabrication techniques and their impact on doping various nanofillers with respective applications. Though PVDF is renowned for its significant applications such as sensors, actuators, energy harvesting and biomedical devices, a tabular chart has been specially framed in one‐liners which highlights the real‐time experimental outcomes where PVDF can be specified as a futuristic polymer for multifunctional applications. A few reports resulted that with increasing graphite and MWCNT fillers into PVDF film, the EMI shielding effectiveness value rose to 14.64 dB at a frequency of 8‐12 Hz. A few reports resulted that by adding ZnO and BaTiO3, the electrical output increased significantly, which is more suitable as a nanogenerator. After an extensive literature survey, we found that reviews are very limited and restricted to specific applications and properties. This review is an overall brief explanation of enormous research works carried out by various experts and presented in a modest way with pictorial and tabular representation for the convenience of researchers. Finally, this review attempts to provide source material to direct researchers towards a fertile area of research with a better understanding of the fundamentals and advancement of polymer piezoelectric materials.

Effect of blue light bleaching in a high TL sensitivity natural quartz crystal

The quartz dating can be performed from optically stimulated luminescence (OSL) or thermoluminescence signals (TL). The relationship between OSL and TL signals is important to ensure adequate measurement of luminescent signal. The bleaching effect on TL signals have been studied by various works. However, there is no consensus. This study investigates the effect of blue light bleaching in a natural quartz crystal whose TL signal can be recorded with test-doses lower than 1 Gy. As a result, it was found that blue light is capable to erode almost completely de first TL peak. The bleaching effect for TL peaks above 200 °C is limited. However, TL components peaked at 320 and 390 °C are more sensitive to blue light than the intermediate TL components peaking at 250 and 280 °C.

Internal Radiation Levels in Natural Quartz Crystals Collected from Southwestern Nigeria; Implications on Thermoluminescence Studies

The relationship between natural thermoluminescence (TL) signal, activity concentrations and the TL sensitivities of twelve (12) quartz samples from different origins were investigated in this study. Gamma spectrometry measurements on the samples were carried out with coaxial-type Germanium detectors (Canberra Industries Inc., Meriden, CT, USA). The TL measurements on the samples were measured using a RISØ TL/OSL reader (model TL/OSL–DA–15). Concentrations of radionuclide activities were only detected in three samples with very low values as compared with world’s average. The highest dose rate in one of the samples was observed to be a factor of 15 lesser than a case of self-dose reported in the literature. The three samples with detectable activity concentrations are the one that possess highest TL signals. All the samples with an exception of one exhibit dependence of sensitization factor of 110 °C TL glow-peak on the equivalent dose (ED). This observation suggested a correlation between the ED of quartz and the sensitization factor of its 110 °C TL peak, an indication of the importance of ED in quartz TL and Optically Stimulated Luminescence (OSL) characteristics. There was no possibility of self-dose effect in all the samples and their radiation safety in exploration and applications in electronics and gemology are validated.

Hydrogen diffusion mechanisms in quartz: insights from H–Li,2H–H and2H–H–Li exchange experiments

AbstractThe diffusivity and diffusion mechanisms of hydrogen together with with deuterium and lithium, parallel to thecaxis of quartz, were investigated experimentally at 800°C, 0.1 GPa with the activity of H2O or2H2O ≈ 1 [2H is used throughout this work to describe deuterium rather than D, to avoid confusion with the diffusion coefficient,D]. The pH was set using mixtures of H2O (or2H2O) and HCl. Three types of experiment were conducted: (1) H-in/Li-out; (2)2H-in/H-out; and (3)2H-in/H + Li out, using three different natural quartz crystals as starting materials. Profiles of H,2H and Li were measured using Fourier-transform infrared (FTIR) spectroscopy and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). H,2H and Li are charge-compensated by Al3+replacing Si4+, or by excess O2–. The total atomic concentration of monovalent cations appears to remain constant over the duration of the experiments. The resulting diffusion profiles are different for the three experimental designs and three starting materials, and some show complex shapes inconsistent with simple diffusion. A multi-site diffusion–reaction model is developed, with the theory based on previous models that have been derived mainly on the basis of conductivity measurements. In these models, the monovalent cations move away from their charge-balancing ion then diffuse rapidly to another site. The mobility of the monovalent cations is described by both a diffusion coefficient and an equilibrium constant that enables dissociation of the immobile charge-balanced defects. This model can describe complex step-shaped profiles formed in H-in/Li-out experiments, profiles with local maxima ('humped’ profiles) in2H-in/H + Li out experiments, and error function-shaped profiles in2H-in/H-out and previously published Li-in/H-out experiments. Our data provide support for models previously proposed for quartz. Studies of the lengths and forms of diffusion profiles from such experiments provide a useful complement to assertions from conductivity experiments.

Confirmation of slow Ti diffusion in quartz by diffusion couple experiments and evidence from natural samples

Titanium diffusion profiles in natural quartz crystals have become an increasingly popular tool to reconstruct the time scales of various magmatic, metamorphic, and hydrothermal processes. However, the original calibration of Ti diffusion rates in quartz has recently been challenged, and diffusivities were found to be about three orders of magnitude lower. We performed annealing experiments on crystal-crystal diffusion couples consisting of Ti-free synthetic quartz seeds over which Ti-rich quartz (100–3000 μg/g Ti) was grown hydrothermally. The annealing experiments were performed at 1000–1600 °C and 0.1 MPa to 2.0 GPa, and they lasted for 3–84 days. The resulting diffusion profiles were mapped by cathodoluminescence (CL), transmission electron microscope–energy-dispersive X-ray spectroscopy (TEM-EDXS), and, for the first time, by helium ion microscope–secondary ion mass spectrometry (HIM-SIMS). Obtained diffusion coefficients range from values similar to the lower range in previous research to values up to two orders of magnitude lower. In addition, inversely zoned quartz and sanidine phenocrysts in a natural rhyolite were studied. Comparison of the diffusion profiles suggests that at ~735 °C, the Ti diffusivity in quartz is ~1.5 and 3.0 orders of magnitude lower than that of Ba and Sr, respectively, in sanidine. The combined evidence confirms that Ti diffusion in quartz is very slow, potentially even slower than proposed earlier. Consequently, previous time scales derived from Ti diffusion profiles in quartz are likely orders of magnitude too short, and further experiments are necessary to fully clarify the issue.

An eruption chronometer based on experimentally determined H-Li and H-Na diffusion in quartz applied to the Bishop Tuff

The diffusion of hydrogen in natural hydrothermal quartz crystals was studied between 657–956°C at atmospheric pressure and various oxygen fugacity (fO2) conditions. Single crystals of OH-bearing quartz were dehydrated in the presence of Li or Na-enriched powders to induce Li-H or Na-H exchange, with the resulting diffusion profiles measured by both Fourier transform infrared (FTIR) spectroscopy and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). Diffusion parallel to [0001], i.e. the crystallographic c-axis, is described by:log10⁡D(m2s−1)=−6.5±0.3+−100.4±5.2kJmol−12.303RT where log10D is the base 10 logarithm of the diffusion coefficient, R is the gas constant and T is the temperature in kelvins, and uncertainties are 1 σ. Diffusion is not affected by (fO2) in this system. Diffusion perpendicular to [0001] is consistently slower, but quantitative constraints cannot be obtained from our data given experimental limitations. This diffusivity is primarily associated with H+-Li+ (or H+-Na+, Na+-Li+) exchange, where the H+ and Li+ are charge-balanced by tetrahedrally-coordinated Al3+. A faster mechanism may also exist where the monovalent cations are charge balanced by excess oxygen. The final defect population, as imaged by FTIR spectroscopy and LA-ICP-MS, likely results from a combination of diffusion and inter-site rearrangement of the monovalent cations. Regardless of such complexities, the determined Arrhenius relationship should be applicable for natural volcanic quartz crystals from the Bishop Tuff, California, wherein H+ is associated with Al3+, and H loss from quartz preceding and/or accompanying the eruption is charge-balanced by Li-gain, without Al movement. Li and H profiles from an example quartz crystal suggest that it experienced eruption/cooling timescales of just 16 minutes to 2.4 hours, showing the considerable promise of using frozen H diffusion profiles in quartz to extract timescales and thus elucidate the last moments of such explosive silicic eruptions.

Multi-technique study of He+ micro-irradiation effects on natural quartz crystals contained in archaeological pottery

The effect of α irradiation on natural quartz is commonly known in geology, resulting in the formation of luminescent halos around radioactive inclusions. In archaeological ceramics quartz grains are present and can be surrounded by radioisotopes contained in the clay. The aim of this study is a first attempt to detect similar halos on the outer rims of quartz grains isolated from archaeological pottery. Such identification could be of interest in luminescence dating and as an alternative method for ceramic artworks authentication. Isolated grains were characterized with cathodoluminescence imaging, SEM-EDX and Raman spectroscopy. Some of the crystals were irradiated for reference with a microbeam of He+ accelerated ions and investigated by means of real-time ionoluminescence. Obtained results seem to confirm that the natural effect on archaeological quartz might be too weak to be detected with these techniques and underline the importance of the multi-technique approach to avoid misinterpretations.

Nanoparticles of Iron Oxides in Thin Films on the Surfaces of Natural Quartz Crystals

The results of studying the nanomorphology of thin films on the faces of quartz rhomboherons from the Sinilga ore occurrence (Subpolar Urals, Russia) are given. Monodisperse hollow nanoparticles of roundish shape constituted probably by iron oxides were discovered using atomic-force and electron microscopy. The hollow structure of nanoparticles was ascribed to the nanoscale Kirkendall effect. The role of iron bacteria was assumed as a factor controlling oxidation under the formation of nanoparticles in the films of the surfaces of natural crystals.

Potential development of green and purple colors in colorless natural quartz from geodes in rhyodacites, Serra Geral Group, Brazil

Abstract Colorless quartz can develop a green color when submitted to gamma irradiation and its development is related to the presence of molecular water and hydroxyl groups in the quartz crystalline structure. In the present study, colorless quartz crystals hosted in geodes within rhyodacites of Serra Geral Group, Southern Brazil, were selected to test the potential development of green color. The samples were analyzed by infrared (IR) and thermogravimetric (TGA) techniques, in addition to the Amethyst Factor (fa) method. All samples showed an absorption bands in the IR, indicating possible development of a green or purple color, and fa analysis indicated the samples would develop a green color. All samples became colored after irradiation, presenting color zoning: from colorless to grayish-green, and from grayish-green to slightly purplish. Some samples showed a greenish colored zone and developed an amethyst phantom crystal in its apical portion. In addition, a high content of water in samples that remained colorless after irradiation was detected. It is here interpreted that water concentration varied during quartz crystallization, enabling the development of the green color, and that the excess of water can inhibit the development of radiation-induced color in colorless natural quartz crystals.

Luminescence of natural α-quartz crystal with aluminum, alkali and noble ions impurities

Photoluminescence and thermally stimulated luminescence of synthetic and natural (morion and smoky) α-quartz crystals doped with aluminum and alkali ions were studied. The samples were examined both untreated and subjected to substitution of alkali ions for copper or silver ions. The photoluminescence spectrum of the untreated crystals is characterized with the main blue band around 400 nm (~3.1 eV). The corresponding luminescence center is based on a defect containing aluminum and alkali as compensators in natural and synthetic quartz crystals. Photoluminescence is subjected to thermal quenching and can be detected at high temperatures above 700 K, however the main intensity decay takes place at 200 K. The thermal quenching activation energy is 0.15 ± 0.05 eV and the frequency factor is 3·107 s−1. In the samples with silver ions the main luminescence band is located at ~260 nm (~4.7 eV) with a time constant of ~37 μs at 80 K, and in the samples with copper ions the PL band is at ~ 360 nm (~3.4 eV) with a time constant ~ 50 μs at 80 K. The initial luminescence of crystals is greatly reduced after introduction of noble ions. The luminescence of noble ions quenches at 700 K without drop in intensity at 200 K. For luminescence associated with silver the energy of thermal quenching is 0.7 ± 0.1 eV with a frequency coefficient of 1 · 1013 s−1, and for the luminescence related to copper, these parameters are 0.55 ± 0.1 eV and 1 · 1012 s−1. The differences in intra-center luminescence properties of the same defect containing alkali ions or noble ions are based on differences in electronic transitions. In the case of alkali ions the charge transfer transitions between oxygen and alkali ions. In the case of noble ions absorption – luminescence corresponds to intra ion transitions. Radiation properties are related to trapping of an electron on one valence ion. Created atom moves out of aluminum containing defect. The hole remains on aluminum-oxygen defect. Thermally stimulated luminescence is related to release of atom, it diffusion to aluminum defect with the hole on oxygen and following radiative recombination. Optically stimulated luminescence is explained by the similar process of optical release of excited atom and movement to aluminum defect and recombination of electron with hole.

Study of Abrasive Cutting of Natural Quartz for Manufacturing Piezoelectric Power Generators

The present study is related with the dicing of natural quartz crystals as part of the process manufacturing of a power generator device. Power generation is important, mainly for wifi systems, which use of batteries is restrictive or impossible due short dimensions and difficult of maintenance. The manufacturing dicing process applied in micro electromechanical systems (MEMS) is the main reference for this study, which objective is explores different parameters of dicing process and the impact of it in the final performance of the generator. Failure impregnation and productivity were study in blade and band saw process with different parameters as speed and cutting force. The natural quartz was selected mainly because availability in Brazil and piezoelectric properties. It was obtained substrates AT cutting plan with thickness of 2.5mm and width of 3mm. The material was tested under compressive stress and the correspondent electric signal was obtained.

Morphotypes of the quartz basic rhombohedra and crystallization conditions

An analysis of the combinatorial–morphological types of faceting for a quartz crystal head has provided 23 types of combinations of faces of basic positive and negative quartz rhombohedra, among which three full-face morphotypes are generally observed under natural conditions. The theoretical occurrence rates are obtained for these morphotypes under isotropic growth conditions, and a morphological analysis is performed over seven samples of natural quartz crystals. A method is proposed for estimating some most important parameters of the crystal formation system: the ratio of variation in the central distances to the faces of crystal rhombohedra, which is related to its growth rates; the ratios of the intermediate growth rates of the rhombohedra and prism, the index of infection with Dauphine twins, and the feed dissymmetry factor.

Water redistribution in experimentally deformed natural milky quartz single crystals—Implications for H2O‐weakening processes

AbstractNatural quartz single crystals were experimentally deformed in two orientations: (1) ⊥ to one prism plane and (2) in O+ orientation at 900 and 1000°C, 1.0 and 1.5 GPa, and strain rates of ~1 × 10−6 s−1. In addition, hydrostatic and annealing experiments were performed. The starting material was milky quartz, which consisted of dry quartz with a large number of fluid inclusions of variable size up to several 100 µm. During pressurization fluid inclusions decrepitated producing much smaller fluid inclusions. Deformation on the sample scale is anisotropic due to dislocation glide on selected slip systems and inhomogeneous due to an inhomogeneous distribution of fluid inclusions. Dislocation glide is accompanied by minor dynamic recovery. Strongly deformed regions show a pointed broad absorption band in the ~3400 cm−1 region consisting of a superposition of bands of molecular H2O and three discrete absorption bands (at 3367, 3400, and 3434 cm−1). In addition, there is a discrete absorption band at 3585 cm−1, which only occurs in deformed regions and reduces or disappears after annealing, so that this band appears to be associated with dislocations. H2O weakening in inclusion‐bearing natural quartz crystals is assigned to the H2O‐assisted dislocation generation and multiplication. Processes in these crystals represent recycling of H2O between fluid inclusions, cracking and crack healing, incorporation of structurally bound H in dislocations, release of H2O from dislocations during recovery, and dislocation generation at very small fluid inclusions. The H2O weakening by this process is of disequilibrium nature because it depends on the amount of H2O available.

Effect of irradiation and thermal annealing on quartz materials luminescence

X-ray and gamma-quanta irradiation of radiation-resistant quartz materials including natural and synthetic quartz crystals and high-purity quartzite causes the luminescence in the ultraviolet range (365 nm), thermally stimulated luminescence and radiofrequency electromagnetic emission. Preliminary radiation and thermal annealing improves luminescence properties of quartz materials.

Study of thermoluminescence response of purple to violet amethyst quartz from Balikesir, Turkey

In thermoluminescence (TL) dosimetry, the phosphor amethyst quartz as a thermoluminescent, appears to be one of the materials arousing the highest interest. In this study the dosimetric characteristics of natural amethyst quartz crystals collected from Balikesir–Dursunbey (Turkey) were investigated for the purpose of determination of the general properties that phosphors should have in order to be useful for thermoluminescence dosimetry. The natural thermoluminescence was drained by annealing the powder samples at 450°C for 1.5h. The effects of high temperature annealing, dose response curves, glow curves after a postirradiation annealing, reusability of the samples and storage of trapped electrons in dark at room temperature were clarified through irradiating the samples with the desired exposures by 90Sr/90Y beta particles.Isothermal annealing before and after irradiation was found to have a definite effect upon the TL glow curve of amethyst crystal powder. The same sample varied in sensitivity depending upon its previous thermal and radiation history. The peak heights of the glow peaks were examined with respect to dose response at dose levels between 1Gy and 5kGy. The intermediate temperature (IT) and high temperature (HT) peaks of 230°C and 300°C, respectively, exhibit dose–response curves as superlinear when dose is on the logarithmic scale except the dose response of 300°C peak for the dose values of 1<D<20Gy in which linear dose response was acquired. At the end of the storage time between exposure and readout which was about one month at room temperature, the emitted light reduction was 14% comparing to the initial state. Repeating the measurements of the same sample, exposed with 0.1, 0.5, 0.8 and 1kGy beta exposures, resulted in between 4% and 11% increase in the TL sensitivity of the material.

Spectroscopic Estimation of Geometrical Structure Elucidation in Natural SiO&lt;SUB&gt;2&lt;/SUB&gt; Crystal

This study demonstrate for the first time the geometrical structure change relationship of natural quartz crystal structures with its purity through infrared spectroscopy. Systemetatic investigations of geometrical structure changes of the quartz crystals have been carried out in mid infrared region 500-1000 cm<SUP>-1</SUP> based on the assignment of infrared bands of the structural group SiO<SUB>4</SUB> tetrahedra. The compositional and structural studies were carried out at room temperature by using X-ray fluorescence (XRF) and Fourier transform infrared (FTIR) spectroscopic techniques. The variation of geometrical structure of quartz crystals has been ascertained by comparing the infrared and X-ray fluorescence results. Results depict the variation of crystal size and shift of characteristic peak positions of the studied samples are depends on its purity. The infrared investigation is found to be good for structure elucidation and changes of geometrical crystal structures of the natural quartz crystals.

Characterisation of a Natural Quartz Crystal as a Reference Material for Microanalytical Determination of Ti, Al, Li, Fe, Mn, Ga and Ge

A natural smoky quartz crystal from Shandong province, China, was characterised by laser ablation ICP‐MS, electron probe microanalysis (EPMA) and solution ICP‐MS to determine the concentration of twenty‐four trace and ultra trace elements. Our main focus was on Ti quantification because of the increased use of this element for titanium‐in‐quartz (TitaniQ) thermobarometry. Pieces of a uniform growth zone of 9 mm thickness within the quartz crystal were analysed in four different LA‐ICP‐MS laboratories, three EPMA laboratories and one solution‐ICP‐MS laboratory. The results reveal reproducible concentrations of Ti (57 ± 4 μg g−1), Al (154 ± 15 μg g−1), Li (30 ± 2 μg g−1), Fe (2.2 ± 0.3 μg g−1), Mn (0.34 ± 0.04 μg g−1), Ge (1.7 ± 0.2 μg g−1) and Ga (0.020 ± 0.002 μg g−1) and detectable, but less reproducible, concentrations of Be, B, Na, Cu, Zr, Sn and Pb. Concentrations of K, Ca, Sr, Mo, Ag, Sb, Ba and Au were below the limits of detection of all three techniques. The uncertainties on the average concentration determinations by multiple techniques and laboratories for Ti, Al, Li, Fe, Mn, Ga and Ge are low; hence, this quartz can serve as a reference material or a secondary reference material for microanalytical applications involving the quantification of trace elements in quartz.

Morphological ripening of fluid inclusions and coupled zone-refining in quartz crystals revealed by cathodoluminescence imaging: Implications for CL-petrography, fluid inclusion analysis and trace-element geothermometry

Cathodoluminescence (CL) studies have previously shown that some secondary fluid inclusions in luminescent quartz are surrounded by dark, non-luminescent patches, resulting from fracture-sealing by late, trace-element-poor quartz. This finding has led to the tacit generalization that all dark CL patches indicate influx of low temperature, late-stage fluids. In this study we have examined natural and synthetic hydrothermal quartz crystals using CL imaging supplemented by in-situ elemental analysis. The results lead us to propose that all natural, liquid-water-bearing inclusions in quartz, whether trapped on former crystal growth surfaces (i.e., of primary origin) or in healed fractures (i.e., of pseudosecondary or secondary origin), are surrounded by three-dimensional, non-luminescent patches. Cross-cutting relations show that the patches form after entrapment of the fluid inclusions and therefore they are not diagnostic of the timing of fluid entrapment. Instead, the dark patches reveal the mechanism by which fluid inclusions spontaneously approach morphological equilibrium and purify their host quartz over geological time.Fluid inclusions that contain solvent water perpetually dissolve and reprecipitate their walls, gradually adopting low-energy euhedral and equant shapes. Defects in the host quartz constitute solubility gradients that drive physical migration of the inclusions over distances of tens of μm (commonly) up to several mm (rarely). Inclusions thus sequester from their walls any trace elements (e.g., Li, Al, Na, Ti) present in excess of equilibrium concentrations, thereby chemically purifying their host crystals in a process analogous to industrial zone refining. Non-luminescent patches of quartz are left in their wake. Fluid inclusions that contain no liquid water as solvent (e.g., inclusions of low-density H2O vapor or other non-aqueous volatiles) do not undergo this process and therefore do not migrate, do not modify their shapes with time, and are not associated with dark-CL zone-refined patches.This new understanding has implications for the interpretation of solids within fluid inclusions (e.g., Ti- and Al-minerals) and for the elemental analysis of hydrothermal and metamorphic quartz and its fluid inclusions by microbeam methods such as LA-ICPMS and SIMS. As Ti is a common trace element in quartz, its sequestration by fluid inclusions and its depletion in zone-refined patches impacts on applications of the Ti-in-quartz geothermometer.