Amiantis purpurata and Eurhomalea lenticularis: Two Case Studies of Oriented Mineralization and its Influence on Clam Shells Strength

RAUL EDUARDO BOLMARO

Pucón

Congreso; 9th Internacional Symposium on Biomineralization. From Paleontology to Materials Science. Biomin09; 2005

Mollusks shells are among the most outstanding materials regarding its strength and weight/strength ratio. Micro-structural studies by x-rays techniques have been performed many times on different species. Texture measurements have shown that mineralization does not proceed randomly but actually respectful of particular orientations characteristic of different genera and species. A deeper understanding of the correlation between strength and texture is the purpose of the current presentation. Two species of bivalves, Amiantis purpurata (Veneridae, Lamark, 1818) and Mulinia edulis (Mactridae, King & Broderip, 1832), have been chosen to perform texture, Vickers indentation hardness and Palmqvist cracks measurements. Both present an aragonitic structure in the whole thickness and texture patterns clearly related with crystallographic twinning. Textures are analyzed by Orientation Distribution Function calculations and their intensities are correlated with the strengths.