Pearls are formed within mollusks when an irritant, such as a parasite or a piece of shell, enters the shell. The mollusk secretes layers of nacre (mother- of-pearl) around the irritant as a defense mechanism. Nacre is composed primarily of microscopic crystals of calcium carbonate (CaCO3), mainly in the aragonite form, cemented together by an organic protein matrix called conchiolin.
Pearl is a hard object produced within the soft tissues of a mollusk. Which one of the following is the main constituent of pearl?
Asked in UPSC CDS 2 2017 · Topic: Inorganic Chemistry (Chemistry of Main Group Elements (s-block and p-block))
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