Marble decorative elements used in the basilica are of great interest both from the point of view of the coatings and the liturgical furniture. Most of these marbles were taken mainly from the buildings in the regions of Constantinople. In the decoration of San Marcos criterion of late antiquity continued, taking into account the different symbolic functions of the temple to use colors or compositions.
The most precious stone was red porphyry, linked to the imperial symbolism of late antiquity period associated with purple. In the period when the Venetians built San Marcos, purple, and therefore by porphyry, were linked to powerful empire and own divine symbolism of the Byzantine Empire.
In San Marcos, use of porphyry is associated with solutions aimed at highlighting the political greatness of Venice and its glory, without any religious implications. Stone of this color can be seen in the group of Tetrarchs in the corner of the Treasury, highlighting the entrance to the Ducal Palace in columns decorating the central door of the west facade of the Basilica, almost like a bow of triumph, or in the corners of the facade, as delimiting a real space. The only elements inside porphyry found in the "pulpit" originally grandstand Doge, another symbol of power. Sometimes, when not available porphyry, marble Iassense, dark red with white veins that are used especially in wall coverings, but with a unique decorative intention was used.
Another beautiful marble with violet tones and reddish streaks was the marble Docimeum or pavonazzetto, always used in a privileged position as the columns of the apse.
Mosaics