Laser engraver bricks are often used for donor recognition. Donor bricks can be created without the need for sandblasting and paint filling. The heat of the laser transforms the materials of the brick into glass through a process call vitrification. The color of the glass ranges from a very deep, dark green to black, depending on the materials used in the bricks during manufacturing.
Paving or paver bricks, which have less aggregate than a standard brick are manufactured with clay (not concrete), and are designed to be laid flat on the ground. They are different from the type made to be used vertically for walls and chimneys.