Blog Bespoke Gift for a Autumn/Winter Birthday These lovely studs were commissioned for a daughters birthday present. The 3mm brown Australian diamonds were chosen especially for their light colour. We set them in rich 18ct yellow gold that was cast in beach sand. As a result, these sandcast studs have a lovely warmth about them. Metal choice makes a huge difference to the overall look and feel of the piece. Had a white gold been chosen for this commission the result would have been quite different.