Calcite and Aragonite CaCO

Calcite is a calcium carbonate, CaCOs, with a rhombohedral cell consisting of the large planar CO3 groups, which contain a Ca ion at the center of an 

The color of calcite can be due to its iron content, which is present as Fe, to Mn , to radiation damage centers, which often involve rare earth 

The natural aragonite in our study consisted of 12 samples from a variety of geologic environments. By using laser-induced time-resolved spectroscopy we were able to detect the following emission centers Mn, Sm and Dy.  

Danburite is calcium borosilicate with an orthorhombic structure (2/m2/ mljm) and space group Pnam. The natural danburite in our study consisted of five samples from a variety of geologic environments. Concentrations of potential luminescence impurities in one sample are presented in Table 4.8. 

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Calcite and aragonite = CaCOs (shells of coccoliths and foraminifera, corals)... 

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