Make the diamonds out of sequins, coloured foil and glitter powder.
Alternatively, paint a cross-section of the Earth - part-underground and part-above. For the explosive eruption of the diamonds, try flicking paint on to paper using a toothbrush.
KS 3-5: Make diamonds the theme of the annual leaving ball. Everyone attending must wear something with a diamond shape on it. Mathematically-minded art students can produce the hall centrepiece decoration - a dodecahedron made from standard-length garden plant supports joined together with elastic bands. To do this, measure half the diagonal of a skeleton cube. Using sticks of this length, build pyramids on all six faces of the cube. This produces a rhombic dodecahedron with 12 diamond-shaped faces (each made up of two pyramids). Clad the facets with silver foil, hang from the ceiling and project light on it.