Query about question "Porcelain" [13105]

https://toefl.gregmat.com/practice/?problem=porcelain


For this question, my main doubt is what is the main inference to complete the second sentence. The paragraph talks about porcelain as a material, its uses etc. I couldn’t come up with the “valued” part of the solution - there’s no hint/ inference that is talking about its value. Anyone have any techniques that makes solving this easier or is it just an educated guess?