It's a big expensive car. <denominal adjective, fact>
 It's an expensive big car. <emphatic: central adjective, opinion>
Central adjectives: both are opinion
 It's a silly cute puppy. (It's more silly than cute)
 It's a cute silly puppy. (It's more cute than silly)
I bought a beautiful expensive vase. <opinion "beautiful", fact "expensive">
Note, "expensive" is privy to both central and denonimal adjectival classes, whereas "beautiful" is not. That is, it can never be a fact adjective. The rule of thumb is, denominal adjectives reside closest to the noun, central adjectives further away. Given that distribution, the order "an expensive beautiful vase" is possible, given emphasis (see below), but normally awkward because 'beautiful' is a central adjective, so it should occur before a denominal adjective.
Max: I bought a beautiful vase.
Sam: It looks like an expensive "beautiful vase" to me. <opinion>
Note, intelligent is also a denominal adjective. Go figure.
- For Teachers