ABSTRACT

DTA-TG study on several aragonites was carried out to clarify the transformation of aragonite to calcite through heating process. Aragonite formed in biological system started and completed the transformation at temperatures lower than did aragonite formed in inorganic systems. The DTA-TG study showed that weight loss was observed at the appearance of endotherm for coral aragonite and inorganically synthesized aragonites, where the release of water during heating was recognized. Water contained in aragonite seems to have an important role for the transformation through heating.