Question

The main component of the pearl is:
A. $NaHCO_3$
B. $CaCO_3$
C. Chitin
D. Conchiolin

Answer 1

Hint: Pearl formation is a defense mechanism seen in mollusks. They are hard and white in color.

Complete answer:
1. Pearls are made of calcium carbonate ($CaCO_3$).
2. Pearls are hard objects. They are formed inside the tissue of the mantle of the shell-like organism known as mollusks. They are composed of calcium carbonate and fluorapatite.
3. The calcium carbonate molecules are arranged in minute crystalline forms. These are deposited in concentric layers which results in the spherical and ovoid shapes of pearls.

Additional Information:
1. The White South Sea pearls are ranked the third most popular type of pearl and also the most expensive. They are cultured in Australia using the silver-lipped Pinctada maxima saltwater oysters. 2. 2. These pearls are considered the "queen of gems".
3. Extraction of pearls from the oysters is known as pearl harvesting. This is done without killing the oysters. They are not killed so that they can be recycled for further harvesting.
4. The gulf nations, central America, Australia, Oceania, etc. Are some of the famous pearl harvesting nations.
5. Since pearls are primarily composed of calcium carbonate, they can be easily dissolved in vinegar. 6. The calcium carbonate is susceptible to erosion even to weakly acidic solutions like acetic acid. The crystals react with the acetic acid that is present in vinegar to form calcium acetate and carbon dioxide.
7. Chitin is the polysaccharide covering of arthropods and fungi.

So, the correct answer is “Option B $CaCO_3$”.

Note:
1. Artificial pearls are also known as faux pearls. They are cultured by forceful exploitation of pearl forming mollusks like oysters. They are of not much market value. They are manufactured by forceful infection of oysters with various pathogens
2. The pearls are basically a hard-calcareous shell around the weak and killed cells