My OperaInclusions in Quy Chau ruby of Vietnam and their origin
Saturday, March 28, 2009 8:20:57 AM
By: Pham Van Long1*, Hoang Quang Vinh2, Nguyen Xuan Nghia3[/ALIGN]
1.Centre for Gem and Gold Research and Identification, 91 Dinh Tien Hoang, Hanoi, Vietnam *Author coresspondence: Pham Van Long, Centre for Gem and Gold Research and Identification, 91 Dinh Tien Hoang, Hanoi, Vietnam. E-mail: lngphamvan@fyahoo.com
2.Institute of Geological Sciences, NCNST, Nghia Do, Cau Giay, Hanoi, Vietnam
3.Institute of Materials Science, NCNST, Nghia Do, Cau Giay, Hanoi, Vietnam
Abstract: In this paper we present the study of the inclusions in ruby from Quy Chau. The gemological characters of the inclusions were examinated by optical microscopy technique. Its compositions were analysed by Raman scattering and SEM (Scanning Electron Microprobe) methods. An assemblage of anatase, andalusite, anorthite, apatite, biotite, boemite, brookit, calcite, corundum, diaspore, dolomite, graphite, margarite, muscovite, phlogopite, pyrite, rutile, zircon and zoizite inclusion were found. Especially, the compositions of gas - liquid phase in multi-phase inclusions and negative crystals were discribed. The forming conditions and origin of the host ruby have been discussed.
Materials and methods
The samples were collected by the authors during diffirent field works. The samples used for this study consisted of faceted rubies, rough and polished samples.
The inclusion features were examined under gemmological microscope with Gemolite instrument. The inclusions first are discriminated and discribed in shape and color characteristics, in their optical and distribution features and are photographed before being introduced into SEM methods or Raman spectroscope for futher study.
All Raman spectra of inclusions in ruby are registered in LABRAM-1B Raman micro spectrum device of Jobin - Yvon firm. LABRAM-1B measuring system is an integral system joined with Olimpus BX40 optical microscope.
Raman spectrum measurements are realized via crystal surface or via specimen section. The searching for inclusions and the choosing of measurement point are realized by means of object lens with a 50 times magnifying power, with a working distance of 8mm length and the diameter of converged laser trace is about 3 m. Spectroscopy light is reconcentrated by inverse spectroscopy and transmitted to the spectrometer entrance. To avoid the very strong fluorescence of ruby in the zone of 640-745mm wave - length, we have used stimulating light with 488,0nm wave - length of argon laser. The collecting source is Charge coupled device (CCP) refrigerated by peltier battery working in visible zone. Raman spectrum measurements are realized by a device making 1800 streaks/mm.
Study results
- Mineral inclusions already found consist of: anatase, andalusite, anorthite, apatite, biotite, boemite, brookit, calcite, corundum, diaspore, dolomite, graphite, margarite, muscovite, phlogopite, pyrite, rutile, zircon and zoizite. Others study found sphene and nepheline inclusions (Dao et al, 2001)[3].
- Gas-liquid inclusions consist of diphasic and multiphasic inclusions distributed as negative crystals. They are primary or secondary inclusions which develop accordingly to their growing structure or to the cracks healed with gaseous phase components (generally CO2, H2S). Especially, for the first time, liquid inclusions containing the combination of CO2-H2S-COS-S8-AlO(OH) were found.
Characteristics of some inclusions are as follow:
Apatite: In ruby from Quy Chau, apatite can be at the same time protogenetic and syngenetic inclusions. Being protogenetic inclusions they are generally corroded shape. Whereas for syngenetic inclusions, their complete original hexagonal prismatic shape is still maintained (Figure 1). Apatite inclusions are generally in yellowish color or colorless. They are transparent and in low relief. Regarding repartition characteristics, apatite inclusions are generally distributed together with phlogopite, calcite, rutile and zircon in which the most popular composition is apatite - calcite - phlogopite.
Bao thể apatit
Calcite: is one of the most popular inclusions found in almost studied specimens of Quy Chau mines. They are generally in many different shapes (Figure 2). They can be relatively complete crystals with their cleavage system or can be uncompleted corroded crystals. At Quy Chau calcite inclusions are generally distributed together with zircon, corundum, apatite, rutile and the compositions of calcite - anatase - apatite (Figure 5); calcite - rutile - zircon - corundum; calcite - corundum - apatite were generally found.
Bao thể calcit
Rutile: Is a rather popular inclusion. In ruby, rutile exists generally with many different shapes, including complete prismatic crystals (Figure 3), spindle-shaped, or fiber shaped crystals which are results of the exsolution process. In the shape of complete crystals, rutile inclusions are generally in redish-brown color with metallic or semi-metallic lustre and in many of them, their knee-twin phenomenon can be observed. These rutile inclusions can be round or angular crystals; this proved that they could be formed at different stages in comparison with corundum crystals.
The second types of rutile inclusions are needles and very thin fiber inclusions. These inclusions are formed by the exsolution processes at later stage. The appearance and concentration of these inclusions make cloud, milky effects which are very popular.
Bao thể rutin
Zircon: Most of zircon inclusions are protogenetic. They are generally corroded and have no more complete crystal shape. Characteristics of zircon at Quy Chau are of colorless and transparent inclusions with high relief and strong diamond lustre (Figure 4). Besides, a characterizing mark of zircon is the apparition of "haloes" radioactive rims around inclusions. These rims are the result of radioactive element disintegration in the components of inclusions themselves: Generated stresses increased the volume of inclusions and beget destructions around them. In Quy Chau ruby, zircon inclusions are generally distributed together with rutile and calcite.
Bao thể zircon
Beside principal inclusions which are mentioned above, in study processes we found the compositions of anorthite and andalusite (Figure 6) and the mica inclusions that was a transitional mineral between muscovite and phlogopite (Figure 7). The presence of these inclusions in Quy Chau ruby provided helpful informations to debate the origin of host ruby (see the discussion below). Morever a number of inclusions such as dolomite, pyrite (Figure 8), graphite (Figure 9), phlogopite, muscovite, and zoisite are found with a less degree of popularity. Pyrite and zoisite inclusions are for the first time discovered and described in Quy Chau ruby. Pyrite is generally of a faded copper yellow color with uncompleted cubic crystal shape since its edges have been slightly corroded. Zoisite is the typical inclusion for ruby from Quy Chau and it also indicated for the metamorphism origin of ruby here.
Gas - liquid inclusions: Gas - liquid inclusions in Quy Chau ruby are existing in two shapes: primary (Figure10) and secondary inclusions. Gas - liquid primary inclusions are formed at the same time with the growing up processes of ruby crystals and are covered by host crystals. Inclusions of this type are generally monophasic or diphasic and some time triphasic, their characteristic shape is spherical or flat and many times they are negative crystals. Secondary inclusions are formed after ruby and sapphire crystals have been completely grown up; their apparition is generally relative to the cracks, which are filled up by liquid and then healed up. These inclusions are generally in fingerprint and feather type. Components of liquid inclusions with determined gaseous phase are generally CO2 and H2S. CO2 is registered by Raman peak at 3580-3700cm-1 while H2S is determined by Raman peak at 2603cm-1. Diaspore is found either as very rare solid inclusions, as prismatic crystals or as a non visible film coating the wall of the whole inclusion cavity. Diaspore was identified by its Raman lines at 331 and 448 cm-1, respectively. Native sulphur is present at room temperature, as very rare solid globules in the inclusions but it is commonly nucleated from a non visible thin layer during laser irradiation. S8 was identified by its characteristics peaks at 220 and 462 cm-1. It is worth noting that COS molecules were identified by their Raman line at 857 cm-1.
Discussions
- Inclusions composition which have been discovered in Quy Chau ruby is very diversified and abundant that proved the multi-origins of the ruby formation in Quy Chau. If inclusions were individually separated, each of them could be formed in different kind of origin, but the association of them in the same specimen determined a certainly condition of their formation or in other words, a determined kind of origin. The composition of inclusions in ruby from Quy Chau can be classified in two origins, including metamorphism and metasomatism. The typical inclusions of metamorphism are anatase, diaspore, muscovite, andalusite, anorthite, zoisite, and CO2-H2S-COS-S8-AlO(OH)-bearing fluid inclusions. The co-existence of anorthite and andalusite inclusions in ruby from Quy Chau proved the host ruby were formed from mica minerals, that related to the metamorphic reaction:
CaAl4Si2O10(OH)2 -> CaAl2Si2O8 + Al2SiO5 + Al2O3 + H2O
margarite -> anorthite + andalusite + ruby
Besides, analyzed result of mica inclusion in Quy Chau ruby (figure 6) gave SiO2=44.44%; Al2O3=33.26%; MgO=8.20%; K2O=10.00%; TiO2=1.56%; F=2.54%. This compositions were typical in high content of Al2O3 (nearly the same with the content of Al2O3 in muscovite) and low content of MgO (closed to the content of MgO in phlogopite). For this reason, we can conclude that this mica inclusion were the transitional mineral between muscovite and phlogopite and it is indicated the existence of metamorphic reaction to form ruby from dolomite and muscovite:
3CaMg(CO3)2 + KAl3Si3O10(OH)2 -> KMg3(AlSi3O10)(OH)2 + 3CaCO3 + Al2O3 + 3CO2
dolomite + muscovite -> phlogopite + calcite + ruby
The typical inclusions of metosomatism origin are calcite, dolomite, apatite, phlogopite and pyrite that related to the dolomite-marble formation in Quy Chau area.
- The popularity of corundum inclusions in ruby and moreover the development of gas - liquid inclusions in both primary and secondary type have proved the multi - stage character in the formation of ruby at Quy Chau area. Corresponding to each stage is a determined formation phase of ruby which results in the distribution of ruby on a large area and related to different geological formation.
Acknowlegement
The authors wish to thank Dr. Nguy Tuyet Nhung for scientific discussion. Thank to Mrs. Nguyen Thu Hoa from V-ICT Corp. for correcting this manuscript.
References
1. Deer W. A. et al.,(1992), The rock-forming minerals, 2nd Edition. Longman Group UK Ltd.
2. Giuliani G., Hoang Quang Vinh, Lhomme T., Dubessy J., Banks D., Fallick T.,Virginie G., Ohnenstetter D., Trinh Phan Trong, Long Pham Van (2003) CO2-H2S-COS-S8-AlO(OH)-bearing fluid inclusions in ruby from marble-hosted deposits in Luc Yen and Quy Chau, North Vietnam. Abstract GAC-MAC-SEG Joint Annual Meeting, Vancouver, Canada, May 25-28, pp. 317.
3. N. Q. Dao; Delaigue L, (2001) Etudes des inclusions dans les rubys Vietnamiens par spectrometries optiques. International Workshop on Material Characterization by Solid state spectroscopy: Gem and Mineral of Vietnam. Hanoi, April, 4-10th , 2001.
4. Pham Van Long 1996 Preliminary results of the study on the genesis and the forming conditions of curundum at Luc Yen mine. Journal of Geology, A/237. Ha Noi.
5. Pham Van Long (1999). Journal of Geology A/252, 21-28, Ha Noi.
6. Spear F. S. (1993) Metamorphism. Mineralogical Society of America, Michigan, USA.
Figure caption
Figure 1. Sharply defined hexagonal crystal of apatite inclusion provides an unmistakable of its presence in Quy Chau ruby, magnification 35x.
Figure 2. Calcite inclusions in Quy Chau ruby are recognized by their cleavage feature, magnification 28x.
Figure 3. Assemblage of inclusions of rutile (pear shape) and apatite (corroded forms) in Quy Chau ruby, magnification 30x.
Figure 4. Zircon inclusion occurs together with the swirl features, magnification 40x
Figure 5. Raman spectrum of calcite, apatite and anatase inclusions in the samse sample of ruby from Quy Chau.
Figure 6. SEM image of anorthite and andalusite inclusions
Figure 7. Spectrum and SEM image of a transitional mica inclusions
Figure 8. SEM image of well-formed and little corroded of pyrite inclusion, magnification 300x.
Figure 9. SEM image of plates of graphite inclusions, magnification 300x.
Figure 10. Primary liquid inclusions that contained CO2-H2O-COS and sulfur (S).
1.Centre for Gem and Gold Research and Identification, 91 Dinh Tien Hoang, Hanoi, Vietnam *Author coresspondence: Pham Van Long, Centre for Gem and Gold Research and Identification, 91 Dinh Tien Hoang, Hanoi, Vietnam. E-mail: lngphamvan@fyahoo.com
2.Institute of Geological Sciences, NCNST, Nghia Do, Cau Giay, Hanoi, Vietnam
3.Institute of Materials Science, NCNST, Nghia Do, Cau Giay, Hanoi, Vietnam
Abstract: In this paper we present the study of the inclusions in ruby from Quy Chau. The gemological characters of the inclusions were examinated by optical microscopy technique. Its compositions were analysed by Raman scattering and SEM (Scanning Electron Microprobe) methods. An assemblage of anatase, andalusite, anorthite, apatite, biotite, boemite, brookit, calcite, corundum, diaspore, dolomite, graphite, margarite, muscovite, phlogopite, pyrite, rutile, zircon and zoizite inclusion were found. Especially, the compositions of gas - liquid phase in multi-phase inclusions and negative crystals were discribed. The forming conditions and origin of the host ruby have been discussed.
Materials and methods
The samples were collected by the authors during diffirent field works. The samples used for this study consisted of faceted rubies, rough and polished samples.
The inclusion features were examined under gemmological microscope with Gemolite instrument. The inclusions first are discriminated and discribed in shape and color characteristics, in their optical and distribution features and are photographed before being introduced into SEM methods or Raman spectroscope for futher study.
All Raman spectra of inclusions in ruby are registered in LABRAM-1B Raman micro spectrum device of Jobin - Yvon firm. LABRAM-1B measuring system is an integral system joined with Olimpus BX40 optical microscope.
Raman spectrum measurements are realized via crystal surface or via specimen section. The searching for inclusions and the choosing of measurement point are realized by means of object lens with a 50 times magnifying power, with a working distance of 8mm length and the diameter of converged laser trace is about 3 m. Spectroscopy light is reconcentrated by inverse spectroscopy and transmitted to the spectrometer entrance. To avoid the very strong fluorescence of ruby in the zone of 640-745mm wave - length, we have used stimulating light with 488,0nm wave - length of argon laser. The collecting source is Charge coupled device (CCP) refrigerated by peltier battery working in visible zone. Raman spectrum measurements are realized by a device making 1800 streaks/mm.
Study results
- Mineral inclusions already found consist of: anatase, andalusite, anorthite, apatite, biotite, boemite, brookit, calcite, corundum, diaspore, dolomite, graphite, margarite, muscovite, phlogopite, pyrite, rutile, zircon and zoizite. Others study found sphene and nepheline inclusions (Dao et al, 2001)[3].
- Gas-liquid inclusions consist of diphasic and multiphasic inclusions distributed as negative crystals. They are primary or secondary inclusions which develop accordingly to their growing structure or to the cracks healed with gaseous phase components (generally CO2, H2S). Especially, for the first time, liquid inclusions containing the combination of CO2-H2S-COS-S8-AlO(OH) were found.
Characteristics of some inclusions are as follow:
Apatite: In ruby from Quy Chau, apatite can be at the same time protogenetic and syngenetic inclusions. Being protogenetic inclusions they are generally corroded shape. Whereas for syngenetic inclusions, their complete original hexagonal prismatic shape is still maintained (Figure 1). Apatite inclusions are generally in yellowish color or colorless. They are transparent and in low relief. Regarding repartition characteristics, apatite inclusions are generally distributed together with phlogopite, calcite, rutile and zircon in which the most popular composition is apatite - calcite - phlogopite.
Bao thể apatit
Calcite: is one of the most popular inclusions found in almost studied specimens of Quy Chau mines. They are generally in many different shapes (Figure 2). They can be relatively complete crystals with their cleavage system or can be uncompleted corroded crystals. At Quy Chau calcite inclusions are generally distributed together with zircon, corundum, apatite, rutile and the compositions of calcite - anatase - apatite (Figure 5); calcite - rutile - zircon - corundum; calcite - corundum - apatite were generally found.
Bao thể calcit
Rutile: Is a rather popular inclusion. In ruby, rutile exists generally with many different shapes, including complete prismatic crystals (Figure 3), spindle-shaped, or fiber shaped crystals which are results of the exsolution process. In the shape of complete crystals, rutile inclusions are generally in redish-brown color with metallic or semi-metallic lustre and in many of them, their knee-twin phenomenon can be observed. These rutile inclusions can be round or angular crystals; this proved that they could be formed at different stages in comparison with corundum crystals.
The second types of rutile inclusions are needles and very thin fiber inclusions. These inclusions are formed by the exsolution processes at later stage. The appearance and concentration of these inclusions make cloud, milky effects which are very popular.
Bao thể rutin
Zircon: Most of zircon inclusions are protogenetic. They are generally corroded and have no more complete crystal shape. Characteristics of zircon at Quy Chau are of colorless and transparent inclusions with high relief and strong diamond lustre (Figure 4). Besides, a characterizing mark of zircon is the apparition of "haloes" radioactive rims around inclusions. These rims are the result of radioactive element disintegration in the components of inclusions themselves: Generated stresses increased the volume of inclusions and beget destructions around them. In Quy Chau ruby, zircon inclusions are generally distributed together with rutile and calcite.
Bao thể zircon
Beside principal inclusions which are mentioned above, in study processes we found the compositions of anorthite and andalusite (Figure 6) and the mica inclusions that was a transitional mineral between muscovite and phlogopite (Figure 7). The presence of these inclusions in Quy Chau ruby provided helpful informations to debate the origin of host ruby (see the discussion below). Morever a number of inclusions such as dolomite, pyrite (Figure 8), graphite (Figure 9), phlogopite, muscovite, and zoisite are found with a less degree of popularity. Pyrite and zoisite inclusions are for the first time discovered and described in Quy Chau ruby. Pyrite is generally of a faded copper yellow color with uncompleted cubic crystal shape since its edges have been slightly corroded. Zoisite is the typical inclusion for ruby from Quy Chau and it also indicated for the metamorphism origin of ruby here.
Gas - liquid inclusions: Gas - liquid inclusions in Quy Chau ruby are existing in two shapes: primary (Figure10) and secondary inclusions. Gas - liquid primary inclusions are formed at the same time with the growing up processes of ruby crystals and are covered by host crystals. Inclusions of this type are generally monophasic or diphasic and some time triphasic, their characteristic shape is spherical or flat and many times they are negative crystals. Secondary inclusions are formed after ruby and sapphire crystals have been completely grown up; their apparition is generally relative to the cracks, which are filled up by liquid and then healed up. These inclusions are generally in fingerprint and feather type. Components of liquid inclusions with determined gaseous phase are generally CO2 and H2S. CO2 is registered by Raman peak at 3580-3700cm-1 while H2S is determined by Raman peak at 2603cm-1. Diaspore is found either as very rare solid inclusions, as prismatic crystals or as a non visible film coating the wall of the whole inclusion cavity. Diaspore was identified by its Raman lines at 331 and 448 cm-1, respectively. Native sulphur is present at room temperature, as very rare solid globules in the inclusions but it is commonly nucleated from a non visible thin layer during laser irradiation. S8 was identified by its characteristics peaks at 220 and 462 cm-1. It is worth noting that COS molecules were identified by their Raman line at 857 cm-1.
Discussions
- Inclusions composition which have been discovered in Quy Chau ruby is very diversified and abundant that proved the multi-origins of the ruby formation in Quy Chau. If inclusions were individually separated, each of them could be formed in different kind of origin, but the association of them in the same specimen determined a certainly condition of their formation or in other words, a determined kind of origin. The composition of inclusions in ruby from Quy Chau can be classified in two origins, including metamorphism and metasomatism. The typical inclusions of metamorphism are anatase, diaspore, muscovite, andalusite, anorthite, zoisite, and CO2-H2S-COS-S8-AlO(OH)-bearing fluid inclusions. The co-existence of anorthite and andalusite inclusions in ruby from Quy Chau proved the host ruby were formed from mica minerals, that related to the metamorphic reaction:
CaAl4Si2O10(OH)2 -> CaAl2Si2O8 + Al2SiO5 + Al2O3 + H2O
margarite -> anorthite + andalusite + ruby
Besides, analyzed result of mica inclusion in Quy Chau ruby (figure 6) gave SiO2=44.44%; Al2O3=33.26%; MgO=8.20%; K2O=10.00%; TiO2=1.56%; F=2.54%. This compositions were typical in high content of Al2O3 (nearly the same with the content of Al2O3 in muscovite) and low content of MgO (closed to the content of MgO in phlogopite). For this reason, we can conclude that this mica inclusion were the transitional mineral between muscovite and phlogopite and it is indicated the existence of metamorphic reaction to form ruby from dolomite and muscovite:
3CaMg(CO3)2 + KAl3Si3O10(OH)2 -> KMg3(AlSi3O10)(OH)2 + 3CaCO3 + Al2O3 + 3CO2
dolomite + muscovite -> phlogopite + calcite + ruby
The typical inclusions of metosomatism origin are calcite, dolomite, apatite, phlogopite and pyrite that related to the dolomite-marble formation in Quy Chau area.
- The popularity of corundum inclusions in ruby and moreover the development of gas - liquid inclusions in both primary and secondary type have proved the multi - stage character in the formation of ruby at Quy Chau area. Corresponding to each stage is a determined formation phase of ruby which results in the distribution of ruby on a large area and related to different geological formation.
Acknowlegement
The authors wish to thank Dr. Nguy Tuyet Nhung for scientific discussion. Thank to Mrs. Nguyen Thu Hoa from V-ICT Corp. for correcting this manuscript.
References
1. Deer W. A. et al.,(1992), The rock-forming minerals, 2nd Edition. Longman Group UK Ltd.
2. Giuliani G., Hoang Quang Vinh, Lhomme T., Dubessy J., Banks D., Fallick T.,Virginie G., Ohnenstetter D., Trinh Phan Trong, Long Pham Van (2003) CO2-H2S-COS-S8-AlO(OH)-bearing fluid inclusions in ruby from marble-hosted deposits in Luc Yen and Quy Chau, North Vietnam. Abstract GAC-MAC-SEG Joint Annual Meeting, Vancouver, Canada, May 25-28, pp. 317.
3. N. Q. Dao; Delaigue L, (2001) Etudes des inclusions dans les rubys Vietnamiens par spectrometries optiques. International Workshop on Material Characterization by Solid state spectroscopy: Gem and Mineral of Vietnam. Hanoi, April, 4-10th , 2001.
4. Pham Van Long 1996 Preliminary results of the study on the genesis and the forming conditions of curundum at Luc Yen mine. Journal of Geology, A/237. Ha Noi.
5. Pham Van Long (1999). Journal of Geology A/252, 21-28, Ha Noi.
6. Spear F. S. (1993) Metamorphism. Mineralogical Society of America, Michigan, USA.
Figure caption
Figure 1. Sharply defined hexagonal crystal of apatite inclusion provides an unmistakable of its presence in Quy Chau ruby, magnification 35x.
Figure 2. Calcite inclusions in Quy Chau ruby are recognized by their cleavage feature, magnification 28x.
Figure 3. Assemblage of inclusions of rutile (pear shape) and apatite (corroded forms) in Quy Chau ruby, magnification 30x.
Figure 4. Zircon inclusion occurs together with the swirl features, magnification 40x
Figure 5. Raman spectrum of calcite, apatite and anatase inclusions in the samse sample of ruby from Quy Chau.
Figure 6. SEM image of anorthite and andalusite inclusions
Figure 7. Spectrum and SEM image of a transitional mica inclusions
Figure 8. SEM image of well-formed and little corroded of pyrite inclusion, magnification 300x.
Figure 9. SEM image of plates of graphite inclusions, magnification 300x.
Figure 10. Primary liquid inclusions that contained CO2-H2O-COS and sulfur (S).
