What is a common characteristic of ceramic-processed gems?

Ceramic-processed gems are known for their uniform grain structure, which results from specific manufacturing techniques that involve high temperatures and controlled atmospheres. This uniformity contributes to the overall homogeneity of the gem material, allowing for consistent color and clarity throughout the stone. The controlled processing conditions enable the creation of a dense and stable structure, which is one of the key features of ceramic stones. This characteristic often enhances the aesthetic qualities of the stones and can also improve their overall durability, distinguishing them from natural gems that may have irregularities in their crystalline structures.

While other options such as high porosity or low melting point may apply to certain materials, they are not defining traits of ceramic-processed gems. High brittleness, on the other hand, is not a typical characteristic associated with these gems in the context of their processed nature; rather, the focus is on the uniformity in structure and the resultant strength from the processing methods used.