The secondary ion mass spectrum of silicon sputtered by high energy C-60(+) ions in sputter equilibrium is found to be dominated by Si clusters and we report the relative yields of Si-m(+) (1 <= m <= 15) and various SimCn+ clusters (1 <= m <= 11 for n = 1; 1 <= m <= 6 for n = 2; 1 <= m <= 4 for n = 3). The yields of Si-m(+) clusters up to Si-7(+) are significant (between 0.1 and 0.6 of the Si+ yield) with even numbered clusters Si-4(+) and Si-6(+) having the highest probability of formation. The abundances of cluster ions between Si-8(+) and Si-11(+) are still significant (> 1% relative to Si+) but drop by a factor of similar to 100 between Si-11(+) and Si-13(+). The probability of formation of clusters Si-13(+)-Si-15(+) is approximately constant at similar to 5x10(-4) relative to Si+ and rising a little for Si-15(+), but clusters beyond Si-15 are not detected (Si-m >= 16(+)/Si+ < 1x10(-4)). The probability of formation of Si-m(+) and SimCn+ clusters depends only very weakly on the C-60(+) primary ion energy between 13.5 keV and 37.5 keV. The behaviour of Si-m(+) and SimCn+ cluster ions was also investigated for impacts onto a fresh Si surface to study the effects that saturation of the surface with C-60(+) in reaching sputter equilibrium may have had on the measured abundances. By comparison, there are very minor amounts of pure Si-m(+) clusters produced during C-60(+) sputtering of silica (SiO2) and various silicate minerals. The abundances for clusters heavier than Si-2(+) are very small compared to the case where Si is the target. The data reported here suggest that Si-m(+) and SimCn+ cluster abundances may be consistent in a qualitative way with theoretical modelling by others which predicts each carbon atom to bind with 3-4 Si atoms in the sample. This experimental data may now be used to improve theoretical modelling. (C) 2010 Elsevier B.V. All rights reserved.