Vaterite Deposition During Eggshell Formation in the Cormorant, Gannet and Shag, and in ‘Shell-less’ Eggs of the Domestic Fowl.

Crystal orientation in the shell of the domestic fowl: An electron diffraction study

“…Changes in the structure of the outer shell layer of different avian species have been referred to on a number of occasions. For example, vaterite, a different polymorph of calcium carbonate, was identified in certain sea birds [14] while amorphous calcium phosphate was detected in the surface regions of the Great Crested Grebe [15]. In the hen's egg the crystal structure remains the same although the crystal size is reduced, and some preferred orientation is developed such that {10i4} planes of the calcite lattice tend to be aligned parallel to the shell surface.…”

Antimicrobial properties of a nanostructured eggshell from a compost-nesting bird

“…Elemental analysis showed high concentrations of phosphorus on the layer of spheres of the brush-turkey cuticle, which likely corresponds to the presence of calcium phosphate (Board, 1982). A cuticle composed of calcium phosphate is rare compared with the more common calcium carbonate (vaterite) or the most ubiquitous organic cuticle (glycoprotein), and has only been found in eggshell cuticles of greater flamingos and guinea fowl (Tullett et al, 1976), grebes (Board et al, 1984) and Mallee fowl . Unlike glycoproteins and vaterite, calcium phosphate does not dissolve in water and thus would not be easily destroyed by exposure to rain or mud in the nest.…”

Micro-structure and chemical composition of vateritic deformities occurring in the bivalve Corbicula fluminea (Müller, 1774)

“…In biological systems, microbial activity might induce vaterite precipitation (Giralt et al, 2001;Lowenstam, 1981;Rodriguez-Navarro et al, 2007) and a number of higher organisms are also known to normally produce vateritic mineralised tissues, e.g. some Ascidiacea (Lowenstam and Abbott, 1975), Gastropoda (in egg shells and associated reproductive tissue) (Hall and Taylor, 1971;Kessel, 1933;Meenakshi et al, 1974), Actinopterygii (Carlström, 1963;Gauldie, 1993;Oliveira et al, 1996) and Aves (Gould, 1972;Tullett et al, 1976). In most other instances of its occurrence however, vaterite seems to be a product of dysfunctional or pathogenic mineralisation processes, such as in the otoliths of some fishes (Gauldie, 1986;Melançon et al, 2005;Palmork et al, 1963;Tomas and Geffen, 2003), freshwater lacklustre pearls (Qiao et al, 2007;Soldati et al, 2008), human biliary and urinary calculi (Palchik and Moroz, 2005;Phemister and Aronsohn, 1939;Prien and Frondel, 1947;Saito et al, 1986) and the shell-less eggs of domestic fowl (Tullett et al, 1976).…”