There has been a news reported about a suspected pearl cost case in a jewelry testing center: Mr. Chou spent nearly USD1,500 to buy one freshwater pearl necklace for his wife, but just after one summer, the pearl necklace that his wife often wears shrank by nearly 1.5mm, and the surface became uneven.
Mr. Chou suspected that he had bought a fake, so he took the pearl necklace to the testing center for identification. But the result was beyond his expectation. The appraisal result showed that the pearl was genuine. The reason why the pearl shrank and became uneven is because of improper wearing and corrosion of acid.
The main mineral components that make up pearls are Aragonite and Calcite (approximately 82%-86%), as well as 10%-14% pearl keratin and 2% moisture. The two minerals that make up pearls are calcium carbonate (CaCO3), the specific gravity of aragonite is 2.95, the hardness is 3.5-4.0, the specific gravity of calcite is 2.71, and the hardness is 3, so the pearl is very fragile.
Because the main component of pearls is calcium carbonate, when pearls come into contact with acidic substances (such as sweat, tap water, etc.), the surface will be damaged. Because its hardness is not high, the friction of some hard objects will also cause damage to the pearls.
In addition, when the pearls contacted with a heat source or a fire source, it would be slowly dried, gradually losing moisture, and the Aragonite will be transformed into calcite, causing the pearl to gradually lose its luster.
If you are a jewelry lover and often buy pearl jewelry, you will know that jewelry needs to be reworked and accessories replaced on a regular basic time.
Post time: Jun-25-2021