h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Sorry to seem picky, but I cringe when I read an oxymoron like 'low natural abundance'. Abundance implies plentiful, and low implies severly limited.

abundance n. A great or plentiful amount. Fullness to overflowing. A greater than sufficient amount.

Perhaps something like:

'The metals form quite a low percentage of the makeup of Earth's crust,'

Or, 'The metals represent a low natural volume of the Earth's crust'

Or, 'The metals comprise a low natural fraction of the materials that form the Earth's crust'

would be better.

Now that I think of it, if its composition is natural, it would be neither abundant or low. It would naturally be just the right natural amount for the Earth's crust, wouldn't it?

It would only be low in reference to other materials, or abundant to our needs.