我们回到原题，这是镁，它很轻。

So, here's magnesium. It's very light.

youdao

橄榄石是一种镁铁硅酸盐，普遍存在于宇宙之中——远之星系，近之彗星。当然，珠宝店也不例外，其宝石级原石被称为贵橄榄石（peridot）。

Olivine is a magnesium iron silicate that exists throughout the universe — in distant galaxies and local comets — as well as in earthly jewelry stores, in a pristine, gem-quality form called peridot.

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介绍了为解决高锰钢铸件的表面化学粘砂现象，结合生产实际，提出将铸件原砂由石英砂改为镁橄榄石砂。

In order to solve the surface chemical scab phenomenon of the high manganese steel casting, the method that replacing quartz sand with magnesium olivine sand was put forward in this paper.

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So, here's magnesium. It's very light.

我们回到原题，这是镁，它很轻。

麻省理工公开课 - 固态化学导论课程节选