This sub-class includes the manufacture of jewellery except costume jewellery. Units in this sub-class are primarily engaged in: •production of: - worked pearls - precious and/or semi-precious stones in the worked state, including the working of industrial quality stones and/or synthetic or reconstructed precious or semi-precious stones •working of diamonds •manufacture of: - jewellery of precious metal or of base metals clad with precious metals, or precious or semi-precious stones, or of combinations of precious metal and/or precious or semi-precious stones or of other materials