Abstract
Mesocrystals attract increasing interest in the fields of physics, chemistry, materials, and Earth sciences. Yet, structural properties of this new class of solid materials are not fully described. Biominerals often display complex hierarchical mesocrystalline organizations. We report on the crystallography of sclerites, which are small (-80 μm), beautifully shaped calcitic biomineral structures found in the living tissues of octocorals. Despite a layered concentric structure, the submicrometer crystalline units constituting the sclerites display a remarkably simple crystallographic organization of similarly oriented units with only a low degree of misorientation between them. Some sclerites display crystallographic sectors, leading to the concept of “mesotwin.” A mesotwin is to a twin what a “mesocrystal” is to a crystal: an analog with defects. On the basis of EBSD data, we propose a simple conceptual crystallographic model that accounts for the observed features. This model involves different rhombohedral unit blocks, with identical shapes and volumes, but different crystallographic faces. EBSD data show that quite unexpectedly slight misorientations of crystallites in the sclerites are not at random but organized around the three equivalent a axes of the hexagonal unit cell of calcite. In a subtle way, the overall organization and morphologies of the red coral sclerites are connected to the calcite crystallography.
© 2015 by Walter de Gruyter Berlin/Boston
Articles in the same Issue
- High-pressure Raman spectroscopic studies of ulvöspinel Fe2TiO4
- Brearleyite, Ca12Al14O32Cl2, a new alteration mineral from the NWA 1934 meteorite
- The 3.65 Å phase in the system MgO-SiO2-H2O: Synthesis, composition, and structure
- Water in upper mantle pyroxene megacrysts and xenocrysts: A survey study
- Mesoscale twinning and crystallographic registers in biominerals
- Radiation effects on cathodoluminescence of albite
- Structure refinement of high-pressure hexagonal aluminous phases K1.00Mg2.00Al4.80Si1.15O12 and Na1.04Mg1.88Al4.64Si1.32O12
- Elastic softening of metamict titanite CaTiSiO5: Radiation damage and annealing
- An experimental study of the diffusion of C and O in calcite in mixed CO2-H2O fluid
- Hydrochemical performance and mineralogical evolution of a dispersed alkaline substrate (DAS) remediating the highly polluted acid mine drainage in the full-scale passive treatment of Mina Esperanza (SW Spain)
- The effect of fO₂ on the partitioning and valence of V and Cr in garnet/melt pairs and the relation to terrestrial mantle V and Cr content
- An experimental study of OH solubility in rutile at 500–900 °C, 0.5–2 GPa, and a range of oxygen fugacities
- The growth interval of garnet in the UHP eclogites from the Dabie orogen, China
- Structural studies of NH4-exchanged natrolites at ambient conditions and high temperature
- Morphology and microstructure of magnetite and ilmenite inclusions in plagioclase from Adirondack anorthositic gneiss
- Thermodynamic properties of stishovite by low-temperature heat capacity measurements and the coesite-stishovite transition boundary
- Mechanisms of Cr and H incorporation in stishovite determined by single-crystal EPR spectroscopy and DFT calculations
- Paramagnetic interactions in the 31P NMR spectroscopy of rare earth element orthophosphate (REPO4, monazite/xenotime) solid solutions
- Garnet sector and oscillatory zoning linked with changes in crystal morphology during rapid growth, North Cascades, Washington
- Phase stability, elastic behavior, and pressure-induced structural evolution of kalsilite: A ceramic material and high-T/high-P mineral
- A new type of high-pressure low-flow metering valve for continuous decompression: First experimental results on degassing of rhyodacitic melts
- Substitution mechanisms and implications for the estimate of water fugacity for Ti-rich phlogopite from Mt. Vulture, Potenza, Italy
- Calibration for IR measurements of OH in apatite
- Electrolytic coloration and spectral properties of natural calcite crystals
- Compositional dependent compressibility of dissolved water in silicate glasses
- In situ monitoring of lepidocrocite bioreduction and magnetite formation by reflection Mössbauer spectroscopy
- Direct determination of europium valence state by XANES in extraterrestrial merrillite: Implications for REE crystal chemistry and martian magmatism
Articles in the same Issue
- High-pressure Raman spectroscopic studies of ulvöspinel Fe2TiO4
- Brearleyite, Ca12Al14O32Cl2, a new alteration mineral from the NWA 1934 meteorite
- The 3.65 Å phase in the system MgO-SiO2-H2O: Synthesis, composition, and structure
- Water in upper mantle pyroxene megacrysts and xenocrysts: A survey study
- Mesoscale twinning and crystallographic registers in biominerals
- Radiation effects on cathodoluminescence of albite
- Structure refinement of high-pressure hexagonal aluminous phases K1.00Mg2.00Al4.80Si1.15O12 and Na1.04Mg1.88Al4.64Si1.32O12
- Elastic softening of metamict titanite CaTiSiO5: Radiation damage and annealing
- An experimental study of the diffusion of C and O in calcite in mixed CO2-H2O fluid
- Hydrochemical performance and mineralogical evolution of a dispersed alkaline substrate (DAS) remediating the highly polluted acid mine drainage in the full-scale passive treatment of Mina Esperanza (SW Spain)
- The effect of fO₂ on the partitioning and valence of V and Cr in garnet/melt pairs and the relation to terrestrial mantle V and Cr content
- An experimental study of OH solubility in rutile at 500–900 °C, 0.5–2 GPa, and a range of oxygen fugacities
- The growth interval of garnet in the UHP eclogites from the Dabie orogen, China
- Structural studies of NH4-exchanged natrolites at ambient conditions and high temperature
- Morphology and microstructure of magnetite and ilmenite inclusions in plagioclase from Adirondack anorthositic gneiss
- Thermodynamic properties of stishovite by low-temperature heat capacity measurements and the coesite-stishovite transition boundary
- Mechanisms of Cr and H incorporation in stishovite determined by single-crystal EPR spectroscopy and DFT calculations
- Paramagnetic interactions in the 31P NMR spectroscopy of rare earth element orthophosphate (REPO4, monazite/xenotime) solid solutions
- Garnet sector and oscillatory zoning linked with changes in crystal morphology during rapid growth, North Cascades, Washington
- Phase stability, elastic behavior, and pressure-induced structural evolution of kalsilite: A ceramic material and high-T/high-P mineral
- A new type of high-pressure low-flow metering valve for continuous decompression: First experimental results on degassing of rhyodacitic melts
- Substitution mechanisms and implications for the estimate of water fugacity for Ti-rich phlogopite from Mt. Vulture, Potenza, Italy
- Calibration for IR measurements of OH in apatite
- Electrolytic coloration and spectral properties of natural calcite crystals
- Compositional dependent compressibility of dissolved water in silicate glasses
- In situ monitoring of lepidocrocite bioreduction and magnetite formation by reflection Mössbauer spectroscopy
- Direct determination of europium valence state by XANES in extraterrestrial merrillite: Implications for REE crystal chemistry and martian magmatism