I was reading a story and the author mentioned that the super-special element made up only half of a percent of the crust. That actually seemed rather large to me, so I googled "composition of the earth's crust" and found the paper
The Composition of the Earth's Crust. Isn't nice when things work out like that.
The section on the crust does not get more specific than 1% (page 39 of pdf), so I went to the next best thing, the section on igneous rocks (page 25 of pdf). That is when things got weird. Apparently, uranium makes up 0.8% and zinc makes up 0.4%.

It gets even worse with lead being 0.2%. I went to the next page for an explanation, and found another table that gives different values for these same elements in MUCH smaller amounts. So I repeat:

.
P.S. What notation is being used on columns 2 and 4 of the table on page 25. At first I thought that it was regular decimal notation, but that would mean that thier estimations for 5 elements, including copper, changed by
>2 degrees of magnitude.