"Más *de*" vs "Más *que*"

"Más *de*" vs "Más *que*"
 

In a story I'm reading, I encountered the following two sentences (in sequence, actually):

"Era, pues, más inteligente de lo que parecía. A lo mejor, hasta era más inteligente que yo".
(Translation: "So, she was more clever than she seemed. She was probably more clever than me").

So, my question is: can anybody explain why the first sentence uses "más...de" while the second uses "más...que"?

"más de lo que" precedes a verb.
"más de" precedes a number, quantity or amount.
"más que" is used when the comparison isn't one of the two conditions above.

so "lo que parecía" is to be thought of as an implied amount?

No, it is simply used when a verb is being compared.

I agree with Rusty, but yes, somehow "más de lo que parecía" implies a certain idea of an "amount" of intelligence the speaker had assumed from the other person. Intelligence is obviously not measured in quantities, but you can more or less compare "how much" intelligence other people possess.

@Jemenake: maybe you will find this thread useful. :)