An apparatus (1; 100; 400) comprising a first device (12; 114; 330a) which is vertically drivable to cause a force to be applied to a first portion of a slab (30; 30'; 1130; 350) to move vertically out of alignment with an area of the slab surrounding the first portion of the slab and thereby introduces a first crack (16; C1) in the first portion of the slab, wherein the first device (12; 114; 330a) is configured to be located between the first portion and a ground surface, when the first crack (16; C1) is introduced; and a device (20, 22; 402) for depositing a material having a color configured to deposit a first material having a color into the first crack (16; C1) of the slab, so that the first crack (16; C1) has the first material deposited becoming a vein having the color of the first material; and further comprising a second device (14; 114; 330b-p) which is vertically drivable to cause a force to be applied to a second portion of the slab (30; 30'; 130; 350) to move vertically out of alignment with an area of the slab (30; 30'; 130; 350) surrounding the second portion of the slab (30; 30'; 130; 350) and thereby introduces a second crack (18; C2) in the second portion of the slab (30; 30'; 130; 350), wherein the second device (14; 114; 330b-p) is configured to be located between the second portion and a ground surface, when the second crack (18; C2) is introduced; wherein the device (20, 22; 402) for depositing a material having a color is configured to deposit a second material having a color into the second crack of the slab (30; 30'; 130; 350), so that the second crack (18; C2) has the second material deposited becoming a vein having the color of the second material; and characterized in that the apparatus (1; 100; 400) is configured so that while the first device (12; 114; 330a) is applying force to the first portion to keep the first crack open, the first crack (16; C1) has the first material deposited, wherein the apparatus (1; 100; 400) is configured so that while the second device (14; 114; 330b-p) is applying force to the second portion to keep the second crack (18; C2) open, the second crack (18; C2) has the second material deposited. a first device (12; 114; 330a) which is vertically drivable to cause a force to be applied to a first portion of a slab (30; 30'; 1130; 350) to move vertically out of alignment with an area of the slab surrounding the first portion of the slab and thereby introduces a first crack (16; C1) in the first portion of the slab, wherein the first device (12; 114; 330a) is configured to be located between the first portion and a ground surface, when the first crack (16; C1) is introduced; and a device (20, 22; 402) for depositing a material having a color configured to deposit a first material having a color into the first crack (16; C1) of the slab, so that the first crack (16; C1) has the first material deposited becoming a vein having the color of the first material; and further comprising a second device (14; 114; 330b-p) which is vertically drivable to cause a force to be applied to a second portion of the slab (30; 30'; 130; 350) to move vertically out of alignment with an area of the slab (30; 30'; 130; 350) surrounding the second portion of the slab (30; 30'; 130; 350) and thereby introduces a second crack (18; C2) in the second portion of the slab (30; 30'; 130; 350), wherein the second device (14; 114; 330b-p) is configured to be located between the second portion and a ground surface, when the second crack (18; C2) is introduced; wherein the device (20, 22; 402) for depositing a material having a color is configured to deposit a second material having a color into the second crack of the slab (30; 30'; 130; 350), so that the second crack (18; C2) has the second material deposited becoming a vein having the color of the second material; and characterized in that the apparatus (1; 100; 400) is configured so that while the first device (12; 114; 330a) is applying force to the first portion to keep the first crack open, the first crack (16; C1) has the first material deposited, wherein the apparatus (1; 100; 400) is configured so that while the second device (14; 114; 330b-p) is applying force to the second portion to keep the second crack (18; C2) open, the second crack (18; C2) has the second material deposited.