Veined Marble Acrylic Dark Green Veins over Green 3/4 in. x 3/4 in. x 5 in. Pen Blank Add the stunning effect of veined marble to your pen with these super-affordable acrylic blanks. Perfect to add class and style to a low or mid priced pen with the look of a marbleized stone appearance. Available in eight combinations veined with rivulets of subtle color running through colorful backgrounds.