  The SiO molecule is one of the candidates for the seed of silicate dust in
the circumstellar envelope of evolved stars, but this opinion is challenged. In
this work we investigate the relation of the SiO maser emis- sion power and the
silicate dust emission power. With both our own observation by using the
PMO/Delingha 13.7-m telescope and archive data, a sample is assembled of 21 SiO
v=1,J=2-1 sources and 28 SiO v=1,J=1- 0 sources that exhibit silicate emission
features in the ISO/SWS spectrum as well. The analysis of their SiO maser and
silicate emission power indicates a clear correlation, which is not against the
hypothesis that the SiO molecules are the seed nuclei of silicate dust. On the
other hand, no correlation is found between SiO maser and silicate
crystallinity, which may imply that silicate crystallinity does not correlate
with mass loss rate.
