What do we call a rare and valuable mineral that can be cut and polished?

A rare and valuable mineral that can be cut and polished is known as a gem. Gems are typically selected for their beauty, rarity, and durability, and they undergo processes like cutting and polishing to enhance their aesthetic appeal and market value. This transformation allows them to be used in jewelry and ornamentation. While quartz is a common mineral and crystals are solid materials whose atoms are arranged in an orderly repeating pattern, they do not necessarily carry the same rarity or value as gems. Aggregate refers to a collection of particles or fragments and is not a term related to individual valuable minerals. Thus, the term gem specifically encapsulates the qualities associated with valuable, polished minerals.