Cosmic dust forms in the circumstellar environments of evolved stars with low and
high masses because the synthesis of dust requires high gas densities and
temperatures. Supernovae are one of these environments and form dust in their ejecta
a few months after their explosion. The harsh physical conditions met in the ejecta
and the absence of hydrogen hamper the production of complex molecular species as
precursors to dust grains. However, dust appears to effectively form in the ejecta
implying that efficient pathways to the synthesis of silicates, metal sulphides and
amorphous carbon from the gas phase are active. I will review former theories of dust
formation in supernovae and present a new approach linking the gas phase to the solid
phase in the ejecta. The various routes to dust relevant to supernova environments
will be discussed as well as new results on dust clusters synthesis in supernovae
with solar metallicity progenitors.