Sand O's Black Acrylic Circle 4"x 4" Moving Sand Pictures. The double-strength glass is framed with a black plastic frame. The black sand is heavier than the white sand so the two will never mix, some of the sands are transparent and some opaque giving the pictures a cool 3-D effect. Pictures may take from minutes to several hours to finish a magical sandscape, tiny air bubbles hold up the sand creating unique natural scenes with every turn.
