Physics and Chemistry of Minerals

, Volume 14, Issue 5, pp 426–434 | Cite as

High-temperature crystal chemistry of phenakite (Be2SiO4) and chrysoberyl (BeAl2O4)

  • Robert M. Hazen
  • Larry W. Finger


Thermal expansion and high-temperature crystal structures of phenakite and chrysoberyl have been determined by x-ray methods at several temperatures to 690° C. Phenakite (hexagonal, space groupR\(\bar 3\)) has slightly anisotropic thermal expansion; average expansions between 25 and 690° C perpendicular and parallel to thec axis are α=5.2×10−6 °C−1 and α=6.4×10−6 °C−1, respectively. The unit cell volume of phenakite over this temperature range is given by the polynomial expression:V = 1102.9(2) + 0.010(2)T + 1.1(3) × 10-5T2.

Chrysoberyl (orthorhombic, space groupPbnm) has nearly isotropic thermal expansion, with maximum expansivity 8.5×10−6 °C−1 parallel to theb axis, and minimum expansivity 7.4×10−6 °C−1 parallel toa. Thec axis expansivity is 8.3×10−6 °C−1. Chrysoberyl volume between 25° and 690° C may be represented by:V = 227.1(2) + 0.003(1)T + 4(2) × 10-6T2.

The thermal expansion of beryllium, aluminum, and silicon cation coordination polyhedra in phenakite and chrysoberyl are similar to values found in previous studies of minerals in the BeO-Al2O3-SiO2 system. High-temperature structure studies of bromellite (BeO), beryl (Be3Al2Si6O18), phenakite and chrysoberyl all have beryllium tetrahedra that display the same near-zero expansion at room temperature, but increasing expansion at higher temperatures.


Thermal Expansion Beryllium Unit Cell Volume Maximum Expansivity Cation Coordination 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Au AY, Hazen RM (1986) Polyhedral modeling of the elastic properties of corundum (α-Al2O3) and chrysoberyl (Al2BeSiO4). Geophys Res Lett 12:725–728Google Scholar
  2. Barton MD (1986) Phase equilibria and thermodynamic properties of minerals in the BeO-Al2O3-SiO2-H2O (BASH) system, with petrologic applications. Am Mineral 71:277–300Google Scholar
  3. Bragg WL, Brown GB (1926) Die Struktur des Olivins. Z Kristallogr 63:538–556Google Scholar
  4. Brown GE Jr, Mills BA (1986) High-temperature structure and crystal chemistry of hydrous alkali-rich beryl from the Harding pegmatite, Taos County, New Mexico. Am Mineral 71:547–556Google Scholar
  5. Downs JW (1983) An experimental examination of the electron distribution in bromellite, BeO, and phenacite, Be2SiO4. Ph.D. Thesis, Virginia Polytechnic Institute and State University, Blacksburg, VirginiaGoogle Scholar
  6. Farrell EF, Fang JH, Newnham RE (1963) Refinement of the chrysoberyl structure. Am Mineral 48:804–810Google Scholar
  7. Finger LW, Hadidiacos CG, Ohashi Y (1973) A computer-automated, single-crystal, X-ray diffractometer. Carnegie Inst Washington, Yearh 72:694–699Google Scholar
  8. Hamilton WC (1974) Angle settings for four-circle diffractometers. In: International Tables for x-ray Crystallography 4:273–284. Kynoch Press, Birmingham, EnglandGoogle Scholar
  9. Hazen RM (1985) Comparative crystal chemistry and the polyhedral approach. Rev Mineral 14:317–346Google Scholar
  10. Hazen RM (1986) High-pressure crystal chemistry of chrysoberyl, Al2BeO4: Insights on the origin of olivine elastic anisotropy. Phys Chem Minerals 14:13–20Google Scholar
  11. Hazen RM (1987) A useful fiction: polyhedral modeling of mineral properties. American Journal of Science, Wones volume, in reviewGoogle Scholar
  12. Hazen RM, Au AY (1986) High-pressure crystal chemistry of phenakite (Be2SiO4) and bertrandite (Be4Si2O7(OH)2). Phys Chem Minerals 13:69–78Google Scholar
  13. Hazen RM, Finger LW (1982) Comparative crystal chemistry. Willey, New YorkGoogle Scholar
  14. Hazen RM, Finger LW (1986) High-pressure and high-temperature crystal chemistry of beryllium oxide. J Appl Phys 59:3728–3733Google Scholar
  15. Hazen RM, Au AY, Finger LW (1986) High-pressure crystal chemistry of beryl (Be3Al2Si6O18) and euclase (BeAlSiO4OH). Am Mineral 71:977–984Google Scholar
  16. Hazen RM, Prewitt CT (1977) Effects of temperature and pressure on interatomic distances in oxides and silicates. Am Mineral 62:309–315Google Scholar
  17. King HE, Finger LW (1979) Diffracted beam crystal centering and its application to high-pressure crystallography. J Appl Crystallogr 12:374–378Google Scholar
  18. Kogure T, Takeuchi Y (1986) Compressibility of the BeO4 tetrahedra in the crystal structure of phenacite. Mineral J 13:22–27Google Scholar
  19. Morosin B (1972) Structure and thermal expansion of beryl. Acta Crystallogr B 28:1899–1903Google Scholar
  20. Robinson K, Gibbs GV, Ribbe PH (1971) Quadratic elongation: a quantitative measure of distortion in coordination polyhedra. Science 172:567–570Google Scholar
  21. Sharp ZD, Hazen RM, Finger LW (1986) Structural refinements of monticellite to 60 kbar. Geol Soc Am Abstracts with Progr 18:746Google Scholar
  22. Zachariasen WH (1967) A general theory of x-ray diffraction in crystals. Acta Crystallogr 23:558–564Google Scholar

Copyright information

© Springer-Verlag 1987

Authors and Affiliations

  • Robert M. Hazen
    • 1
  • Larry W. Finger
    • 1
  1. 1.Carnegie Institution of WashingtonGeophysical LaboratoryWashington, DCUSA

Personalised recommendations