Free‐standing powder of zinc sulphide quantum particles has been synthesized using a chemical route. X‐ray diffraction analysis shows that the diameter of the particles is ∼21±2 A˚ which is smaller than the Bohr exciton diameter for zinc sulphide. UV absorption shows an excitonic peak centered at ∼300 nm corresponding to an energy gap of 4.1±0.1 eV. These particles show a luminescence band at ∼424 nm. The quantum particles could be doped with copper during synthesis without altering the UV absorption or x‐ray diffraction pattern. However, doping shifted the luminescence to 480 nm, green wavelength in the visible region. ©1995 American Institute of Physics.