Study by XRD and EBSD of texture and microstructure of the eggs of Chelonoidis chilensis turtle.

V. TARTALINI; P. RISSO; R.E. BOLMARO ; M.C. AVALOS

Saint George

Conferencia; 18th International Conference on Textures of Materials; 2017

Brigham Young University, Utah.

Calcite and aragonite are the two most important and abundant crystalline forms of CaCO3. Calcite is one of the most abundant minerals in the earth crust. Aragonite, despite being unstable at surface conditions of pressure and temperature, is also present in large mineral deposits. They are almost evenly distributed as mollusk shell bio mineral constituents, either as sole component or combined with each other. In eggs, of avian or reptilian origin, calcite is absolutely dominant. Only some species of land turtles are known being composed of aragonite. This clear distinction attracted attention and drove us to characterize turtle eggs in search for microstructural characteristics and correlation with other species´ eggs.The studies were performed by scanning turtle eggs of Chelonoidis chilensis on the Radial-Tangential planes all through the almost 1 mm thickness. Also X ray pole figures were measure by the reflection Schultz method. The structure resulted in a four layered calcite-aragonite composite material, which probably highly enhance mechanical properties. Resultant textures are correlated with avian and reptilian egg results, form the literature and other species characterized by the same techniques.