The Capital of China is, by far, the 3rd most populated city in the world. Having population of 21.5 million (21,516,000), with a population density of 1,300/km2, it is countryâs center for education, culture and politics. Talking about politics, this city is the hub of politics in the country for, as long as, eight centuries.
A pearl is an organic mineral mixture formed with the soft living tissue of a shelled mollusk.Chemically pearls are made of calcium carbonate, either the mineral aragonite or a mixture of aragonite and calcite, sometimes also with minor vaterite.Pearls are used as gemstones, but are not regarded as true minerals due to their organic origin. pearl is an organic mineral mixture formed with the soft living tissue of a shelled mollusk.
A pearl is a hard object produced within the soft tissue (specifically the mantle) of a living shelled mollusk. Just like the shell of a clam, a pearl is composed of calcium carbonate in minute crystalline form, which has been deposited in concentric layers. The ideal pearl is perfectly round and smooth, but many other shapes (baroque pearls) occur.