  6-14 micron Spitzer spectra obtained at 6 epochs between April 2005 and
October 2008 are used to determine temporal changes in dust features associated
with Sakurai's Object (V4334 Sgr), a low mass post-AGB star that has been
forming dust in an eruptive event since 1996. The obscured carbon-rich
photosphere is surrounded by a 40-milliarcsec torus and 32 arcsec PN. An
initially rapid mid-infrared flux decrease stalled after 21 April 2008.
Optically-thin emission due to nanometre-sized SiC grains reached a minimum in
October 2007, increased rapidly between 21-30 April 2008 and more slowly to
October 2008. 6.3-micron absorption due to PAHs increased throughout. 20
micron-sized SiC grains might have contributed to the 6-7 micron absorption
after May 2007. Mass estimates based on the optically-thick emission agree with
those in the absorption features if the large SiC grains formed before May 1999
and PAHs formed in April-June 1999. Estimated masses of PAH and large-SiC
grains in October 2008, were 3 x 10 -9 Msun and 10 -8 Msun, respectively. Some
of the submicron-sized silicates responsible for a weak 10 micron absorption
feature are probably located within the PN because the optical depth decreased
between October 2007 and October 2008. 6.9 micron absorption assigned to ~10
micron-sized crystalline melilite silicates increased between April 2005 and
October 2008. Abundance and spectroscopic constraints are satisfied if about
2.8 per cent cent of the submicron-sized silicates coagulated to form
melilites. This figure is similar to the abundance of melilite-bearing
calcium-aluminium-rich inclusions in chondritic meteorites.
