I have this sample of a spreadsheet to simplify what I'm trying to do:

In "Formula 1" I'm using a VLOOKUP function within an IF condition to assign value_if_true (and value_if_false) whether the result of the VLOOKUP function, specifically each value in column C, contains the specific text "rock". This gives me no problem when the IF criteria exactly matches the content of the indexed column, as we can see in cell F3.
The problem rises when I have to search for a partial match, as other values in column C contain not only the "rock" text. Using wildcards directly in the IF criteria doesn't work so, searching for this kind of operation, this thread uses COUNTIF to check for specific partial text using wildcards.
I tried to replicate this with my case just substituting the "range" argument of COUNTIF with my VLOOKUP function, as seen in "Formula 2", but in this case the system detects an error within the formula that cannot elaborate. The only thing that I can guess is that the COUNTIF function can't digest a VLOOKUP function as "range".
What other functions or workarounds could I use to instruct the IF condition in returning me the value "true" every time the word "rock" appears in column C?

