Abstract: An apparatus for color blending an agglomerating flowable material from a differently colored individual batches, to mold a mottled heterogeneous product with material from at least two batches so that mottled products (i.e. with irregular arrangement of spots or confluent blotches of color) are produced from a relatively dry concrete mixture (zero slump concrete), which agglomerates into clumps that tumble randomly from individual hoppers containing individually colored concrete batches. By controlling positioning of a filling tray relative to a hopper outlet, the time sequencing and quantity of material released from each hopper outlet, it is possible to fill the filling tray in a large number of seemingly random mottled patterns where clumps of each of the individual colors remain visible in the molded product.