What materials were used for columns in the palaces at Persepolis?

The columns in the palaces at Persepolis were primarily constructed of a dark gray stone sourced from the adjacent mountain, which was often polished to a marble-like surface.12

However, materials varied depending on the specific building:

• Stone: Most of the colossal structures, including the famous columns in the apadana (audience hall) and the Gate of Xerxes, were built using this dark gray stone, which was cut into large blocks and laid without mortar.12
• Wood: In the Treasury, the columns were made of wood that was heavily plastered and painted in bright colors.3

While many of the stone columns were fluted in the Greek manner, the more elaborate capitals and bases often featured a blend of Greek and Egyptian floral treatments. A distinct Achaemenian design element was the "double-figure" impost capital, which typically took the form of paired bulls, bull-men, or dragons.3