[mousquet]

To my knowledge, there's too much sand in North Africa, namely over the Sahara region.

The desert has even been gradually nibbling fertile lands further to the south, which is a major concern, potentially a complete disaster to the Sahel.

But then, sand is probably not valuable enough to be shipped to other continents from there.
Shipping copper or zinc on long distances is economically reasonable and profitable.
Not sand yet.