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Title: Nanoscale Transforming Mineral Phases in Fresh Nacre

Nacre, or mother-of-pearl, the iridescent inner layer of many mollusk shells, is a biomineral lamellar composite of aragonite (CaCO 3) and organic sheets. Biomineralization frequently occurs via transient amorphous precursor phases, crystallizing into the final stable biomineral. In nacre, despite extensive attempts, amorphous calcium carbonate (ACC) precursors have remained elusive. They were inferred from non-nacre-forming larval shells, or from a residue of amorphous material surrounding mature gastropod nacre tablets, and have only once been observed in bivalve nacre. Here we present the first direct observation of ACC precursors to nacre formation, obtained from the growth front of nacre in gastropod shells from red abalone (Haliotis rufescens), using synchrotron spectromicroscopy. Surprisingly, the abalone nacre data show the same ACC phases that are precursors to calcite (CaCO 3) formation in sea urchin spicules, and not proto-aragonite or poorly crystalline aragonite (pAra), as expected for aragonitic nacre. In contrast, we find pAra in coral.
Authors:
 [1] ;  [1] ;  [2] ;  [1] ;  [3] ;  [4]
  1. Univ. of Wisconsin, Madison, WI (United States). Dept. of Physics
  2. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Advanced Light Source
  3. Princeton Univ., NJ (United States). Dept. of Geosciences
  4. Univ. of Wisconsin, Madison, WI (United States). Dept. of Physics. Dept. of Chemistry; Harvard Univ., Cambridge, MA (United States). Radcliffe Inst. for Advanced Study
Publication Date:
Grant/Contract Number:
FG02-07ER15899; AC02-05CH11231; DMR-1105167; BSF-2010065
Type:
Published Article
Journal Name:
Journal of the American Chemical Society
Additional Journal Information:
Journal Volume: 137; Journal Issue: 41; Journal ID: ISSN 0002-7863
Publisher:
American Chemical Society (ACS)
Research Org:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); National Science Foundation (NSF); US-Israel Binational Science Foundation (BSF); Harvard Univ. (United States)
Contributing Orgs:
Harvard Univ., Cambridge, MA (United States); Princeton Univ., NJ (United States)
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; 58 GEOSCIENCES
OSTI Identifier:
1223142
Alternate Identifier(s):
OSTI ID: 1378600