Here are a front and top view of the base with the chinchilla sand glued down. The sand I use is branded as "Charlie Chinchilla Bathing Sand" and marketed by Supreme Petfoods. I bought a 2 litre container for £2.75 ages ago and have used less than half a litre so far.
The dry sand is then painted with slightly watered-down GW brown ink. Capilliary pressure pulls the ink through the sand.