Unique crystallographic pattern in the macro to atomic structure of Herdmania momus vateritic spicules

Lee Kabalah-Amitai, Boaz Mayzel, Paul Zaslansky, Yaron Kauffmann, Peter Clotens, Boaz Pokroy

Research output: Contribution to journalArticlepeer-review


Biogenic vaterite is extremely rare. The only known example of a completely vateritic mineralized structure is the spicule of the solitary ascidian, Herdmania momus. In characterizing the structure of these spicules, using state-of-the-art techniques such as synchrotron X-ray diffraction and synchrotron micro- and nanotomography, we observed a continuous structural pattern from the macro down to the micro, nano, and atomic scales. We show that the spicules demonstrate a unique architecture composed of micron-sized, hexagonally faceted thorns organized in partial spirals along the cylinder-like polycrystalline body of the spicule, and tilted from it at an angle of about 26°. This morphological orientation coincides with the crystallographic orientation relationship between each thorn and the polycrystals within the spicule. Hence the entire spicule grows along the [0. 1. 1] direction of vaterite while the individual thorns grow along the [0. 0. 1] direction. This, together with the presence of both inter- and intra-crystalline organic phases, beautifully displays the organism's ability to achieve perfect control of mineralization biologically while employing an unstable polymorph of calcium carbonate: vaterite.

Original languageEnglish
Pages (from-to)191-198
Number of pages8
JournalJournal of Structural Biology
Issue number2
StatePublished - Aug 2013


  • Ascidians
  • Biogenic crystals
  • Biomineralization
  • Crystallographic orientations
  • High-resolution characterization techniques
  • Vaterite

All Science Journal Classification (ASJC) codes

  • Structural Biology


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