Plant for processing a block of porphyry or stone, the plant including, in a processing line, a processing group including a scanning station or apparatus configured to acquire information about the block, a gripping apparatus, one or more cutting stations (14, 16, 18, 20) or at least one cutting station, and a control unit configured to coordinate the operations of the scanning station or apparatus, the gripping apparatus and the one or more cutting stations (14, 16, 18, 20) in order to identify the certain position of the block of porphyry and determine one or more cutting parameters on the basis of the information detected by the scanning apparatus; wherein the plant comprises at least one manipulator device or member adapted to take the block from the certain position and position it under the shears or blade of the one or more cutting stations (14, 20), and wherein the one or more cutting stations (14, 16, 18, 20) is/are configured to cut the block of porphyry starting from the certain position and on the basis of one or more of the cutting parameters determined by the control unit, characterized in that the scanning station or apparatus is configured to detect the grain and the colour of the block; the gripping apparatus is configured to grip the block from above by suction action and displace the block of porphyry in said certain position along the processing line, wherein the certain position is a spatial position with respective spatial coordinates; wherein said gripping apparatus is located along the processing line between the scanning apparatus and the one or more cutting stations (14, 16, 18, 20); and wherein said at least one manipulator device or member is provided with a respective pincer body or body having two prongs, for retaining the block, wherein the pincer body of the manipulator device or member is adapted to take the block from the certain position and position it under the shears or blade of the one or more cutting stations (14, 20) and wherein said manipulator device or member is a first manipulator device or member and the plant includes a second manipulator device or member provided with a respective pincer body or body having two prongs, for retaining the block, wherein the pincer body of the first manipulator device or member is adapted to take the block from the certain position and position it under the shears or a blade of the cutting station (14, 20), wherein the pincer body of the first manipulator device or member and the pincer body of the second manipulator device or member are arranged and/or configured to hold the block together or simultaneously under the shears or blade of the cutting station (14, 20), and wherein the pincer body of the second manipulator device or member is adapted to grip the block on the opposite side to the pincer body of the first manipulator device or member, relative to the shears, in order to hold a cut part of the block after cutting. the scanning station or apparatus is configured to detect the grain and the colour of the block; the gripping apparatus is configured to grip the block from above by suction action and displace the block of porphyry in said certain position along the processing line, wherein the certain position is a spatial position with respective spatial coordinates; wherein said gripping apparatus is located along the processing line between the scanning apparatus and the one or more cutting stations (14, 16, 18, 20); and wherein said at least one manipulator device or member is provided with a respective pincer body or body having two prongs, for retaining the block, wherein the pincer body of the manipulator device or member is adapted to take the block from the certain position and position it under the shears or blade of the one or more cutting stations (14, 20) and wherein said manipulator device or member is a first manipulator device or member and the plant includes a second manipulator device or member provided with a respective pincer body or body having two prongs, for retaining the block, wherein the pincer body of the first manipulator device or member is adapted to take the block from the certain position and position it under the shears or a blade of the cutting station (14, 20), wherein the pincer body of the first manipulator device or member and the pincer body of the second manipulator device or member are arranged and/or configured to hold the block together or simultaneously under the shears or blade of the cutting station (14, 20), and wherein the pincer body of the second manipulator device or member is adapted to grip the block on the opposite side to the pincer body of the first manipulator device or member, relative to the shears, in order to hold a cut part of the block after cutting.