When talking about "value", you have to consider the literal meanings of words. Invaluable is used to describe something "more precious", as you say.
Valuable is most like "pricey", something that has a high material cost or usefulness. Invaluable is most like "priceless", you are saying that the item is so precious, you cannot put a material value on it.
Invaluable is normally used within the English language to describe immaterial things, such as friendship, knowledge, or even good answers to questions.
Hope this helped!