Stone is considered to be one of the most important raw materials throughout history due to its great durability, as well as its aesthetic values. Colourful stone adorned the most important buildings, captivated the eyes, and spoke of the wealth and status of the owner. In certain periods, Egyptian red porphyry was considered to be of the highest quality and was thus the most valued and the most exclusive. The reasons for this are its purple colour and extreme hardness, strength, and durability – porphyry being considered to be the hardest stone in antiquity. Throughout history, red porphyry has played a central role in imperial self-representation, starting with Roman and Byzantine emperors, up until medieval and modern rulers. Because of its almost exclusive connection with monarchs and their families, it is often called the "imperial stone". It was used in antiquity to make various architectural and artistic objects for the imperial court, and in later periods, due to its popularity, it continued to be used as spolia. The thesis will present the general characteristics of porphyry as a material, and the Egyptian quarry Mons Porphyrites as its only known source. However, the greatest emphasis will be on the history of its use and perception in certain periods, which gradually resulted in the development of its complex symbolism related to the symbolism of the colour purple.