The pearl was mellow, full and great, it is a priceless treasure for human, but a accident with pain for died freshwater mussel, maker of the pearl.

这粒珍珠圆润硕大，在人类而言是无价之宝，可是对珍珠的制造者，死去的蚌来说只是一个带了些痛苦的意外。

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According to Scottish Natural Heritage, 72 of Scotland's rivers support reproducing populations of freshwater pearl mussel including many of the world's largest populations.

BBC: Freshwater pearl mussels