The Coranda-Hondol ore deposit (Certej, Romania) is a sulfide ore deposit that was mined primaril... more The Coranda-Hondol ore deposit (Certej, Romania) is a sulfide ore deposit that was mined primarily for gold, silver, lead, and zinc. Secondary minerals were formed through a precipitation process from sulfate solutions with a high concentration of dissolved metals (especially Fe). These sulfate solutions resulted from acid mine drainage. Fourteen waste samples were analyzed through Raman spectrometry, X-ray diffraction, and scanning electron microscopy. Fe3+-, Fe2+-, Cu-, Zn-, Ca-, Mg-, and MnAl-hydrated sulfates were identified. All are unstable when exposed to the laser beam of the Raman spectrometer. Coquimbite, copiapite, ferricopiapite, hydroniumjarosite, and gunningite turn into anhydrous forms or oxides, depending on the laser power. Gypsum turns into bassanite, while apjohnite loses all water molecules at 53.6 mW laser power on the surface of the sample. Rhomboclase, melanterite, rozenite, antlerite, and brochantite break down without forming new minerals. Fe2+-sulfates do not change into hematite under laser irradiation. Epsomite and hexahydrite are stable at 53.6 mW laser power.
Carpathian Journal of Earth and Environmental Sciences, 2014
Au-Ag- and Ag-tellurides are widely abundant in the vast majority of the “Golden Quadrilateral” (... more Au-Ag- and Ag-tellurides are widely abundant in the vast majority of the “Golden Quadrilateral” (Metaliferi Mts., Romania) ore deposits. Optical microscope observations, electron microprobe and μ-Raman analyses have been successfully carried out to identify Au-Ag-Te minerals from Coranda-Hondol open pit (part of Certej deposit, South Apuseni Mountains, in Romania). The identified tellurides are hessite (Ag2Te), petzite (Ag3AuTe2) and stützite (Ag5-xTe3, where x = 0.24-0.36) and they usually occur as patches (reaching 90-100 μm in length) in galena, bournonite-seligmannite or at the contact between the last three minerals. In general, all the microanalytical data are stoichiometric with a slightly compositional variation in the case of hessite. The μ-Raman spectrum of stützite shows a characteristic Raman fingerprint with a very strong band at 147 cm-1. The broadness of the Raman band (147 cm-1) indicates a non-homogeneous distribution and, in conjunction with the strong heterogeneity observed under microscope, it suggests that the tellurides have formed contemporaneously and they can possibly be attributed to a later silver-rich telluride-bearing substage.
A multi-technique characterization and a provenance study of the black pigment used in Cucuteni p... more A multi-technique characterization and a provenance study of the black pigment used in Cucuteni pottery painting (Neolithic age, Romania) were carried out. 127 Cucuteni shards were analyzed by Raman spectrometry. The main components of this pigment are pyrolusite and/or jacobsite. Hematite and quartz are frequent minor components and Ti oxides were seldom found. The manganiferous corpuscles discovered at Neamţ county (eastern part of Romania) were the raw material of the Cucuteni black pigment. The Mn corpuscles were studied using XRD, Raman, FT-IR and Atomic Absorption Spectrometry. The main components are birnessite, goethite and frequently, quartz. Raw material was subjected to a temperature of 750 °C for 6 h and,once cooled, analyzed through Raman and FT-IR spectrometry. Pyrolusite, hematite and quartz were found in the heated powder sample.► We mention for the first time the source of the black pigment for Cucuteni culture. ► Raw material identified and analyzed through XRD, AAS, FT-IR and Raman spectroscopy. ► Birnessite, goethite and quartz indentified in raw material. ► 127 ceramic shards from Cucuteni culture were analyzed through Raman spectroscopy. ► Pyrolusite, jacobsite, hematite, quartz, black carbon, rutile and anatase.
Raman and infrared spectroscopy has been used to analyze three samples from the Hondol open pit, ... more Raman and infrared spectroscopy has been used to analyze three samples from the Hondol open pit, in order to identify and characterize these samples using vibrational features. The minerals found are secondary hydrated sulfate minerals associated with both the alteration of sulfide-bearing mine wastes and primary minerals.
The minerals found by vibrational spectroscopy are: ferricopiapite Fe3+0.66Fe3+4(SO4)6(OH)2 · 20(H2O); coquimbite Fe3+2(SO4)3 · 9(H2O); and epsomite Mg(SO4) · 7(H2O). The spectral features observed in these minerals allowed four distinct hydrous sulfates to be discriminated without conventional methods, such as XRD or chemical analyzes.
The study shows the potential of Raman and infrared spectroscopy to identify hydrous sulfates very fast, nondestructively, non-invasively, with a very small volume samples.
Both Raman and infrared spectra show the fundamental vibrational modes of SO4 groups. Also, the spectral variations of the internal modes of sulfate tetrahedra were used to discriminate between minerals from the same group, where divalent or trivalent cations from the octahedral sites or H2O in different proportions were the only differences.
Raman and infrared spectral studieswere performed on six natural minerals from the doublechain si... more Raman and infrared spectral studieswere performed on six natural minerals from the doublechain silicate group. We analyzed samples of grunerite, actinolite, tremolite, pargasite (+kaersutite) and riebeckite in order to determine the spectral differencesbetween them and to identify the vibrations that occur. Also, for one sample thought to be pargasitewe obtained the Raman spectrum of kaersutite, while anothersample was determined as a Ti-rich pargasite, since the difference between these two minerals consists in the presence of more than 0.50apfu VITi in kaersutite (titaniferous calcic amphibole). The Raman spectrum of kaersutite exhibits characteristic bands of the VITi-OH vibration around 580–590cm-1 and 750cm-1. These two bands are stronger than the symmetric stretching vibration of the Si-Ob-Si (ν1), which arisesas the strongest band in all otheramphibole minerals ofthe present study, around 650–670cm-1. Both Raman and infrared spectra of all the analyzed samples reveal the presence of Fe2+, Mg2+ or other cations in the octahedral sites, displaying distinct bands in the ~300-450cm-1 spectral region, as well as in the OH stretching region (3600–3700cm-1).
11 fragments of wall painting from the Beroe fortress, Romania (4th –6th century) were analysed t... more 11 fragments of wall painting from the Beroe fortress, Romania (4th –6th century) were analysed through Raman spectroscopy. The yellow-brown pigment on the fragments is jarosite and/or Najarosite. Other than at 445cm-1, the Raman lines of all the spectra are identical. This Raman line is slightly shifted in different spectra, and this fact proves the presence of both jarosite and Najarosite.
Anal Şt Univ Al I Cuza Iaşi Geologie, Jan 1, 2009
Some of the most common carbonates have been investigated by non-contact Raman spectroscopy. The ... more Some of the most common carbonates have been investigated by non-contact Raman spectroscopy. The synthetic alkali carbonates K2CO3 and Na2CO3 have also been studied. The Raman spectrum of aurichalcite is different from that of malachite. This spectrum has a characteristic intense band at 1069 cm-1 which is assigned to the ν1 symmetric stretching mode of the carbonate unit. The two low intensity Raman lines of 1485 and 1507 cm-1 may be ascribed to the ν3 asymmetric stretching modes. To the ν4 mode (doubly degenerate symmetric bending) are attributed the values of 706 cm-1 (ν4a) and 733 cm-1 (ν4b). A number of bands with different intensities are observed in the lowest spectral shift (285, 388, 430, 461 and 498 cm-1). These Raman lines are assigned to the CuO and ZnO stretching and bending vibrations. A single band of the OH-stretching modes is observed at 3344 cm-1.
Analele Stiintifice ale Universitatii Al I …, Jan 1, 2010
Raman spectroscopy is a simple, powerful and fast method to identify and distinguish between diff... more Raman spectroscopy is a simple, powerful and fast method to identify and distinguish between different minerals from the amphibole group of the inosilicate class. We analyzed samples of grunerite, actinolite, nephrite, Cr – actinolite (smaragdite), uralite (var. of actinolite), tremolite, pargasite, glaucophane and riebeckite in order to determine their Raman spectra and their fingerprint. The structure of these amphiboles belongs to the space group C2/m. Also, through this work we intend to show types of linkages between Si and bridging O (Ob) or non-bridging O (Onb), and complex vibrations that occur in all amphibole spectra, corresponding to the symmetric stretching modes (νs) of the Si-Ob-Si bridges or O-Si-O linkages and to the asymmetric stretching modes (νas) of the Si-Ob-Si bridges and O-Si-O linkages. The most distinct Raman peak detected in this Raman study of amphiboles is around 660-675 cm-1, which is assigned to the ν1/νs (symmetric stretching vibrations) of the Si-Ob-Si bridges. Some spectra present two very weak peaks at ~2330 cm-1 and ~2437 cm-1, respectively, due to the substitution of K or Na with H3O+ (K, Na ↔ H3O+) and NH4+ (K, Na ↔ NH4+); these spectral bands were identified at potassium micas.
The black pigment of 112 Cucuteni A and Cucuteni B pottery has been analyzed through Raman spectr... more The black pigment of 112 Cucuteni A and Cucuteni B pottery has been analyzed through Raman spectroscopy. The black pigment contains pyrolusite and jacobsite; quartz and anatase have only accidentally been observed. Black Carbon was also identified, but only in two samples. The spherical or oblate black corpuscles discovered at Feteşti-La Schit (Suceava county) were analyzed by means of X-ray diffractometry and Raman spectroscopy. They consist of Mn ± Fe oxihydroxides and quartz. No Mn carbonates or silicates have been identified. The mineralogical composition of the pigment applied to the pottery shards, as well as that of the raw pigment, together with the use of the same pigment over a long period of time (1100 years), suggest the exploitation of a large.
The Coranda-Hondol ore deposit (Certej, Romania) is a sulfide ore deposit that was mined primaril... more The Coranda-Hondol ore deposit (Certej, Romania) is a sulfide ore deposit that was mined primarily for gold, silver, lead, and zinc. Secondary minerals were formed through a precipitation process from sulfate solutions with a high concentration of dissolved metals (especially Fe). These sulfate solutions resulted from acid mine drainage. Fourteen waste samples were analyzed through Raman spectrometry, X-ray diffraction, and scanning electron microscopy. Fe3+-, Fe2+-, Cu-, Zn-, Ca-, Mg-, and MnAl-hydrated sulfates were identified. All are unstable when exposed to the laser beam of the Raman spectrometer. Coquimbite, copiapite, ferricopiapite, hydroniumjarosite, and gunningite turn into anhydrous forms or oxides, depending on the laser power. Gypsum turns into bassanite, while apjohnite loses all water molecules at 53.6 mW laser power on the surface of the sample. Rhomboclase, melanterite, rozenite, antlerite, and brochantite break down without forming new minerals. Fe2+-sulfates do not change into hematite under laser irradiation. Epsomite and hexahydrite are stable at 53.6 mW laser power.
Carpathian Journal of Earth and Environmental Sciences, 2014
Au-Ag- and Ag-tellurides are widely abundant in the vast majority of the “Golden Quadrilateral” (... more Au-Ag- and Ag-tellurides are widely abundant in the vast majority of the “Golden Quadrilateral” (Metaliferi Mts., Romania) ore deposits. Optical microscope observations, electron microprobe and μ-Raman analyses have been successfully carried out to identify Au-Ag-Te minerals from Coranda-Hondol open pit (part of Certej deposit, South Apuseni Mountains, in Romania). The identified tellurides are hessite (Ag2Te), petzite (Ag3AuTe2) and stützite (Ag5-xTe3, where x = 0.24-0.36) and they usually occur as patches (reaching 90-100 μm in length) in galena, bournonite-seligmannite or at the contact between the last three minerals. In general, all the microanalytical data are stoichiometric with a slightly compositional variation in the case of hessite. The μ-Raman spectrum of stützite shows a characteristic Raman fingerprint with a very strong band at 147 cm-1. The broadness of the Raman band (147 cm-1) indicates a non-homogeneous distribution and, in conjunction with the strong heterogeneity observed under microscope, it suggests that the tellurides have formed contemporaneously and they can possibly be attributed to a later silver-rich telluride-bearing substage.
A multi-technique characterization and a provenance study of the black pigment used in Cucuteni p... more A multi-technique characterization and a provenance study of the black pigment used in Cucuteni pottery painting (Neolithic age, Romania) were carried out. 127 Cucuteni shards were analyzed by Raman spectrometry. The main components of this pigment are pyrolusite and/or jacobsite. Hematite and quartz are frequent minor components and Ti oxides were seldom found. The manganiferous corpuscles discovered at Neamţ county (eastern part of Romania) were the raw material of the Cucuteni black pigment. The Mn corpuscles were studied using XRD, Raman, FT-IR and Atomic Absorption Spectrometry. The main components are birnessite, goethite and frequently, quartz. Raw material was subjected to a temperature of 750 °C for 6 h and,once cooled, analyzed through Raman and FT-IR spectrometry. Pyrolusite, hematite and quartz were found in the heated powder sample.► We mention for the first time the source of the black pigment for Cucuteni culture. ► Raw material identified and analyzed through XRD, AAS, FT-IR and Raman spectroscopy. ► Birnessite, goethite and quartz indentified in raw material. ► 127 ceramic shards from Cucuteni culture were analyzed through Raman spectroscopy. ► Pyrolusite, jacobsite, hematite, quartz, black carbon, rutile and anatase.
Raman and infrared spectroscopy has been used to analyze three samples from the Hondol open pit, ... more Raman and infrared spectroscopy has been used to analyze three samples from the Hondol open pit, in order to identify and characterize these samples using vibrational features. The minerals found are secondary hydrated sulfate minerals associated with both the alteration of sulfide-bearing mine wastes and primary minerals.
The minerals found by vibrational spectroscopy are: ferricopiapite Fe3+0.66Fe3+4(SO4)6(OH)2 · 20(H2O); coquimbite Fe3+2(SO4)3 · 9(H2O); and epsomite Mg(SO4) · 7(H2O). The spectral features observed in these minerals allowed four distinct hydrous sulfates to be discriminated without conventional methods, such as XRD or chemical analyzes.
The study shows the potential of Raman and infrared spectroscopy to identify hydrous sulfates very fast, nondestructively, non-invasively, with a very small volume samples.
Both Raman and infrared spectra show the fundamental vibrational modes of SO4 groups. Also, the spectral variations of the internal modes of sulfate tetrahedra were used to discriminate between minerals from the same group, where divalent or trivalent cations from the octahedral sites or H2O in different proportions were the only differences.
Raman and infrared spectral studieswere performed on six natural minerals from the doublechain si... more Raman and infrared spectral studieswere performed on six natural minerals from the doublechain silicate group. We analyzed samples of grunerite, actinolite, tremolite, pargasite (+kaersutite) and riebeckite in order to determine the spectral differencesbetween them and to identify the vibrations that occur. Also, for one sample thought to be pargasitewe obtained the Raman spectrum of kaersutite, while anothersample was determined as a Ti-rich pargasite, since the difference between these two minerals consists in the presence of more than 0.50apfu VITi in kaersutite (titaniferous calcic amphibole). The Raman spectrum of kaersutite exhibits characteristic bands of the VITi-OH vibration around 580–590cm-1 and 750cm-1. These two bands are stronger than the symmetric stretching vibration of the Si-Ob-Si (ν1), which arisesas the strongest band in all otheramphibole minerals ofthe present study, around 650–670cm-1. Both Raman and infrared spectra of all the analyzed samples reveal the presence of Fe2+, Mg2+ or other cations in the octahedral sites, displaying distinct bands in the ~300-450cm-1 spectral region, as well as in the OH stretching region (3600–3700cm-1).
11 fragments of wall painting from the Beroe fortress, Romania (4th –6th century) were analysed t... more 11 fragments of wall painting from the Beroe fortress, Romania (4th –6th century) were analysed through Raman spectroscopy. The yellow-brown pigment on the fragments is jarosite and/or Najarosite. Other than at 445cm-1, the Raman lines of all the spectra are identical. This Raman line is slightly shifted in different spectra, and this fact proves the presence of both jarosite and Najarosite.
Anal Şt Univ Al I Cuza Iaşi Geologie, Jan 1, 2009
Some of the most common carbonates have been investigated by non-contact Raman spectroscopy. The ... more Some of the most common carbonates have been investigated by non-contact Raman spectroscopy. The synthetic alkali carbonates K2CO3 and Na2CO3 have also been studied. The Raman spectrum of aurichalcite is different from that of malachite. This spectrum has a characteristic intense band at 1069 cm-1 which is assigned to the ν1 symmetric stretching mode of the carbonate unit. The two low intensity Raman lines of 1485 and 1507 cm-1 may be ascribed to the ν3 asymmetric stretching modes. To the ν4 mode (doubly degenerate symmetric bending) are attributed the values of 706 cm-1 (ν4a) and 733 cm-1 (ν4b). A number of bands with different intensities are observed in the lowest spectral shift (285, 388, 430, 461 and 498 cm-1). These Raman lines are assigned to the CuO and ZnO stretching and bending vibrations. A single band of the OH-stretching modes is observed at 3344 cm-1.
Analele Stiintifice ale Universitatii Al I …, Jan 1, 2010
Raman spectroscopy is a simple, powerful and fast method to identify and distinguish between diff... more Raman spectroscopy is a simple, powerful and fast method to identify and distinguish between different minerals from the amphibole group of the inosilicate class. We analyzed samples of grunerite, actinolite, nephrite, Cr – actinolite (smaragdite), uralite (var. of actinolite), tremolite, pargasite, glaucophane and riebeckite in order to determine their Raman spectra and their fingerprint. The structure of these amphiboles belongs to the space group C2/m. Also, through this work we intend to show types of linkages between Si and bridging O (Ob) or non-bridging O (Onb), and complex vibrations that occur in all amphibole spectra, corresponding to the symmetric stretching modes (νs) of the Si-Ob-Si bridges or O-Si-O linkages and to the asymmetric stretching modes (νas) of the Si-Ob-Si bridges and O-Si-O linkages. The most distinct Raman peak detected in this Raman study of amphiboles is around 660-675 cm-1, which is assigned to the ν1/νs (symmetric stretching vibrations) of the Si-Ob-Si bridges. Some spectra present two very weak peaks at ~2330 cm-1 and ~2437 cm-1, respectively, due to the substitution of K or Na with H3O+ (K, Na ↔ H3O+) and NH4+ (K, Na ↔ NH4+); these spectral bands were identified at potassium micas.
The black pigment of 112 Cucuteni A and Cucuteni B pottery has been analyzed through Raman spectr... more The black pigment of 112 Cucuteni A and Cucuteni B pottery has been analyzed through Raman spectroscopy. The black pigment contains pyrolusite and jacobsite; quartz and anatase have only accidentally been observed. Black Carbon was also identified, but only in two samples. The spherical or oblate black corpuscles discovered at Feteşti-La Schit (Suceava county) were analyzed by means of X-ray diffractometry and Raman spectroscopy. They consist of Mn ± Fe oxihydroxides and quartz. No Mn carbonates or silicates have been identified. The mineralogical composition of the pigment applied to the pottery shards, as well as that of the raw pigment, together with the use of the same pigment over a long period of time (1100 years), suggest the exploitation of a large.
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The minerals found by vibrational spectroscopy are: ferricopiapite Fe3+0.66Fe3+4(SO4)6(OH)2 · 20(H2O); coquimbite Fe3+2(SO4)3 · 9(H2O); and epsomite Mg(SO4) · 7(H2O). The spectral features observed in these minerals allowed four distinct hydrous sulfates to be discriminated without conventional methods, such as XRD or chemical analyzes.
The study shows the potential of Raman and infrared spectroscopy to identify hydrous sulfates very fast, nondestructively, non-invasively, with a very small volume samples.
Both Raman and infrared spectra show the fundamental vibrational modes of SO4 groups. Also, the spectral variations of the internal modes of sulfate tetrahedra were used to discriminate between minerals from the same group, where divalent or trivalent cations from the octahedral sites or H2O in different proportions were the only differences.
The minerals found by vibrational spectroscopy are: ferricopiapite Fe3+0.66Fe3+4(SO4)6(OH)2 · 20(H2O); coquimbite Fe3+2(SO4)3 · 9(H2O); and epsomite Mg(SO4) · 7(H2O). The spectral features observed in these minerals allowed four distinct hydrous sulfates to be discriminated without conventional methods, such as XRD or chemical analyzes.
The study shows the potential of Raman and infrared spectroscopy to identify hydrous sulfates very fast, nondestructively, non-invasively, with a very small volume samples.
Both Raman and infrared spectra show the fundamental vibrational modes of SO4 groups. Also, the spectral variations of the internal modes of sulfate tetrahedra were used to discriminate between minerals from the same group, where divalent or trivalent cations from the octahedral sites or H2O in different proportions were the only differences.