Skip to main content
Log in

Structural changes of synthetic opal by heat treatment

  • Original Paper
  • Published:
Physics and Chemistry of Minerals Aims and scope Submit manuscript

Abstract

The structural changes of synthetic opal by heat treatment up to 1,400 °C were investigated using scanning electron microscopy, X-ray diffraction, and Fourier transform infrared and Raman spectroscopies. The results indicate that the dehydration and condensation of silanol in opal are very important factors in the structural evolution of heat-treated synthetic opal. Synthetic opal releases water molecules and silanols by heat treatment up to 400 °C, where the dehydration of silanol may lead to the condensation of a new Si–O–Si network comprising a four-membered ring structure of SiO4 tetrahedra, even at 400 °C. Above 600 °C, water molecules are lost and the opal surface and internal silanol molecules are completely dehydrated by heat effect, and the medium-temperature range structure of opal may begin to thermally reconstruct to six-membered rings of SiO4 tetrahedra. Above 1,000 °C, the opal structure almost approaches that of silica glass with an average structure of six-membered rings. Above 1,200 °C, the opal changes to low-cristobalite; however, minor evidence of low-tridymite stacking was evident after heat treatment at 1,400 °C.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Subscribe and save

Springer+ Basic
$34.99 /Month
  • Get 10 units per month
  • Download Article/Chapter or eBook
  • 1 Unit = 1 Article or 1 Chapter
  • Cancel anytime
Subscribe now

Buy Now

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Fig. 9
Fig. 10
Fig. 11

Similar content being viewed by others

Explore related subjects

Discover the latest articles, news and stories from top researchers in related subjects.

References

  • Bates JB (1972) Raman spectra of α and β cristobalite. J Chem Phys 57:4042–4047

    Article  Google Scholar 

  • Benesi HA, Jones AC (1959) An infrared study of the water–silica gel system. J Phys Chem 63:179–182

    Article  Google Scholar 

  • Brinker CJ, Tallant DR, Roth EP, Ashley CS (1986) Sol–gel transition in simple silicates -structural studies during densification. J Non Cryst Solids 82:117–126

    Article  Google Scholar 

  • Devine RAB, Arndt J (1987) Si-O bond-length modification in pressure-densified amorphous SiO2. Phys Rev B 35:9376-9379

    Google Scholar 

  • Etchepare J, Merian M, Kaplan P (1978) Vibrational normal modes of SiO2. II. Cristobalite and tridymite. J Chem Phys 68:1531–1537

    Article  Google Scholar 

  • Flörke OW (1973) The genesis of Hyalite. Neues Jahrb Mineral Monatsch:82-89

  • Galeener FL (1979) Band limits and the vibrational spectra of tetrahedral glasses. Phys Rev B 19:4292–4297

    Article  Google Scholar 

  • Galeener FL (1982) Planar rings in vitreous silicas. J Non Cryst Solids 49:53–62

    Article  Google Scholar 

  • Graetsch H (1994) Structural characteristics of opaline and microcrystalline silica minerals. Rev Mineral 29:209–232

    Google Scholar 

  • Graetsch H, Flörke OW, Miehe G (1985) The nature of water in chalcedony and opal-C from Brazilian agate geodes. Phys Chem Miner 12:300–306

    Article  Google Scholar 

  • Graetsch H, Gies H, Topalović I (1994) NMR, XRD and IR study on microcrystalline opals. Phys Chem Miner 21:166–175

    Article  Google Scholar 

  • Handke M, Mozgawa W (1993) Vibrational spectroscopy of the amorphous silicates. Vib Spectrosc 5:75–84

    Article  Google Scholar 

  • Hench LL, West JK (1990) The sol–gel process. Chem Rev 90:33–72

    Article  Google Scholar 

  • Humbert B, Burneau A, Gallas JP, Lavalley JC (1992) Origin of the Raman bands, D1 and D2, in high surface area and vitreous silicas. J Non Cryst Solids 143:75–83

    Article  Google Scholar 

  • Jones JB, Segnit ER (1969) Water in sphere-type opal. Mineral Mag 37:357–361

    Article  Google Scholar 

  • Jones JB, Segnit ER (1971) The nature of Opal I. Nomenclature and constituent phases. J Geol Soc Aust 18:57–68

    Article  Google Scholar 

  • Jones JB, Sanders JV, Segnit ER (1964) Structure of opal. Nature 204:990–991

    Article  Google Scholar 

  • Kahraman S, Önal M, Sarikaya Y, Bozdoğan İ (2005) Characterization of silica polymorphs in kaolins by X-ray diffraction before and after phosphoric acid digestion and thermal treatment. Anal Chim Acta 552:201–206

    Article  Google Scholar 

  • Kamiya K, Nasu H (1998) Structure and thermal change of alkoxy-derived silica gel fibers and films. Ceram Trans 81:21–28

    Google Scholar 

  • Kamiya K, Oka A, Nasu H, Hashimoto T (2000) Comparative study of structure of silica gels from different sources. J Sol–Gel Sci Technol 19:495–499

    Article  Google Scholar 

  • Kingma KJ, Hemley RJ (1994) Raman spectroscopic study of microcrystalline silica. Am Miner 79:269–273

    Google Scholar 

  • Langer K, Flörke OW (1974) Near infrared absorption spectra (4,000–9,000 cm−1) of opals and the role of “water” in these SiO2–nH2O minerals. Fortschr Miner 52:17–51

    Google Scholar 

  • McDonald RS (1958) Surface functionality of amorphous silica by infrared spectroscopy. J Am Chem Soc 62:1168–1178

    Google Scholar 

  • Mochizuki S, Kawai N (1972) Lattice vibrational spectra of vitreous silica densified by pressure. Solid State Commun 11:763–765

    Article  Google Scholar 

  • Murray CA, Greytak TJ (1979) Intrinsic surface phonons in amorphous silica. Phys Rev B 20:3368–3387

    Article  Google Scholar 

  • Okudera H, Hozumi A (2003) The formation and growth mechanisms of silica thin film and spherical particles through the Stober process. Thin Solid Films 434:62–68

    Article  Google Scholar 

  • Önal M, Kahraman S, Sarikaya Y (2007) Differentiation of α-cristobalite from opals in bentonites from Turkey. Appl Clay Sci 35:25–30

    Article  Google Scholar 

  • Orcel G, Phalippou J, Hench LL (1986) Structural Changes of silica xerogels during low temperature dehydration. J Non-Cryst Solids 88:114–130

    Article  Google Scholar 

  • Orcel G, Hench LL, Artaki I, Jonas J, Zerda TW (1988) Effect of formamide additive on the chemistry of silica sol–gels II. Gel structure. J Non Cryst solids 105:223–231

    Article  Google Scholar 

  • Ostrooumov M, Eritsch E, Lasnier B, Lerfrant S (1999) Spectres Raman des opals: aspect diagnostique et aide à la classification. Eur J Mineral 11:899–908

    Google Scholar 

  • Sanders JV (1964) Colour of precious opal. Nature 204:1151–1153

    Article  Google Scholar 

  • Sen PN, Thorpe MF (1977) Phonons in AX2 glasses: from molecular to band-like modes. Phys Rev B 15:4030–4038

    Article  Google Scholar 

  • Sharma SK, Mammone JF, Nicol MF (1981) Raman investigations of ring configurations in vitreous silica. Nature 292:140–141

    Article  Google Scholar 

  • Shimada Y, Okuno M, Syono Y, Kikuchi M, Fukuoka K, Ishizawa N (2002) An X-ray diffraction study of shock-wave-densified SiO2 glasses. Phys Chem Min 29:233–239

    Article  Google Scholar 

  • Smallwood AG, Thomas PS, Ray AS (1997) Characterisation of sedimentary opals by Fourier transform Raman spectroscopy. Spectrochim Acta A 53:2341–2345

    Article  Google Scholar 

  • Sosman RB (1955) New and old phase diagram of silica. Trans Br Ceram Soc 54:655–670

    Google Scholar 

  • Stolen RH, Walrafen GE (1976) Water and its relation to broken bond defects in fused silica. J Chem Phys 64:2623–2631

    Article  Google Scholar 

  • Tan CZ, Arndt J (1999) X-ray diffraction of densified silica glass. J Non Cryst Solids 249:47–50

    Article  Google Scholar 

  • Wahl FM, Grim RE, Graf B (1961) Phase transformations in silica as examined by continuous X-ray diffraction. Am Miner 46:196–208

    Google Scholar 

Download references

Acknowledgments

This work was supported JSPS KAKENHI [Grant-in-Aid for Challenging Exploratory Research] Grant Number 24654172. This work also was supported by Grant-in-Aid for Joint research between Kanazawa University and JAIST in 2011–2012. A part of this work was conducted in Kyoto-Advanced Nanotechnology Network, supported by “Nanotechnology Network” of the Ministry of Education, Culture, Sports, Science and Technology, Japan.

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Akane Arasuna.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Arasuna, A., Okuno, M., Okudera, H. et al. Structural changes of synthetic opal by heat treatment. Phys Chem Minerals 40, 747–755 (2013). https://doi.org/10.1007/s00269-013-0609-1

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s00269-013-0609-1

Keywords

Navigation