Magnesium and phosphorus distribution in the avian eggshell

M. Cusack*, A. C. Fraser, T. Stachel

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

45 Citations (Scopus)


Magnesium and phosphorus are major inorganic constituents of the avian eggshell. The Mg/Ca ratio has been used as a palaeothermometer in a range of calcite biominerals. Eggshells provide the opportunity to examine the Mg/Ca ratio of a calcite biomineral produced in a constant temperature environment. Mg distribution is not constant throughout the shell, decreasing from nucleation until after fusion of the mammillary caps and then increasing to termination. This indicates that temperature of deposition is not the only factor controlling the Mg content of this biomineral system. There is a greater increase in magnesium concentration in the outer region of eggshells from older birds. The variation in magnesium concentration does not appear to correlate with organic content. Phosphorus occurs in the outer quarter of the eggshell and rises to termination and is therefore not confined to cuticular vesicles.

Original languageEnglish
Pages (from-to)63-69
Number of pages7
JournalComparative Biochemistry and Physiology - Part B: Biochemistry and Molecular Biology
Issue number1
Publication statusPublished - 1 Jan 2003
Externally publishedYes


  • Calcite
  • Eggshell
  • Magnesium
  • Mg/Ca ratio
  • Palaeothermometer
  • Phosphorus


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