The suffix -an -en is always added to the verbs and gives the structure 'relative in active form' to the verb. For example: Giden adam - The man who goes/is going etc. Or only Giden - The one who goes/is going etc. So olan means ... Which happens/is/becomes etc. (Olmak means to be, to become, to happen etc.) So değerli olan can mean: Değerli olan ev: the house which is valuable. Değerli olan söz: the remark/the word which is worthy Değerli olan budur: this is what is worthy / this is the one which is worthy. But when you use only değerli, that means you use adjective. Şuradaki ev değerlidir - that house/the house there is valuable. Değerli bir insandır - he is a worthy person. Etc. So when you see a verb which ends with -an -en, remember there is a relative clause in it. As a result the answer of your question is: one is relative clause, but the other is adjective.

the thing which is precious one