Aliasing jewel → gem
Link to alias

Reason:

They are practically the same thing and the latter has nearly three times as many posts tagged with it.

Technically a gem is short for gemstone, which refers to the raw material (ruby, diamond, etc), while jewel refers to a gemstone that has been cut, dressed, and set into a proper piece of jewelry (which obtains its name from that distinction).

In e621's case though, such a distinction is unimportant.

tony311 said:
In e621's case though, such a distinction is unimportant.

I didn't say it did, just saying that that's what the actual definition separation is, is all.

Alias approved I suppose, since it doesn't seem needed to have both