What is a natural pearl, and how are they formed?

什么是天然珍珠? 它们又是如何形成的呢?

Natural pearls are hard to find.

很难找到天然珍珠。

So a natural pearl would have all of those concentric layers of growth from the very inside out.

天然珍珠从里到外都生长着这些同心层。

And embellished by a chain featuring natural irregular baroque pearls, as you can see.

如您所见，饰有一条带有天然不规则巴洛克珍珠的链条。

Natural pearls form when some kind of irritant, usually a small organism, makes its way into the shell of a mollusk like an oyster or a mussel.

当某种刺激物，（通常是一种小生物），进入牡蛎或贻贝等软体动物的外壳时，天然珍珠就可以形成了。

He says that part of the reason the Marie Antoinette pearl is worth so much is because it's a natural pearl, which brings us to one quality that determines a pearl's value.

他说，玛丽·安托瓦内特的珍珠之所以价值不菲，部分原因在于它是天然珍珠，这是决定珍珠价值的品质之一。