Aragonite - what it is?

Aragonites are Calcium carbonate crystals found in pearl.
In December 2009 issue of ProteinSpotlight, a very interesting protein is featured. This protein complex is none other than the one that gives luster to pearl. The complex is made out of three proteins, known as the Pif complex in which is found pearlin, Pif80 and Pif97. Pif80 and 97 are part of the same sequence which is subsequently cleaved into two.Pif80 – by way of its many asparagine residues – binds to calcium carbonate and not only elicits aragonite crystal formation but also has a role in the orientation of the aragonite crystals. Here is the Full link to the article..