Diamonds may be a symbol of loving partnership and a girl’s best friend, but are they also becoming a close friend to organised crime? There is growing evidence of organised crime syndicates becoming involved in the lucrative international diamond trade. Found only in certain regions of the world, diamonds are a finite natural resource—often difficult to mine. Limited abundance combined with strong consumer demand for gem-quality stones make diamonds a highly valued commodity. Desire by criminal operators to tap into this wealth through illicit means has encouraged the growth of theft and fraud within the diamond industry. Furthermore, diamonds are being used in certain parts of the world to finance more insidious activities including drug and arms dealing. On 22 October 2001, the Australian Institute of Criminology held a roundtable meeting on “Illicit Aspects of the Diamond Industry”, where many of these issues were examined by stakeholders from government and industry. This paper explores the nature of illicit activity within the diamond industry, reviews Australia’s experience with diamond-related crime, and considers potential responses.