Samples are generally taken with a hammer and chisel. Back in the laboratory they are cut into small blocks with a diamond saw (Pict. 1) to fit the mouth of the rock-crusher (Pict. 2). They are crushed and sieved to obtain a sample grain size of between 0.25 and 0.6 mm. The samples are treated with aqua regia to remove carbonates and organic matter and then washed to neutral and dried. The samples are then leached on a shaker (Pict. 3) in order to prepare the surface for froth flotation which removes feldspar and mica.