  Dust production among post-main-sequence stars is investigated in the
Galactic globular cluster 47 Tucanae (NGC 104) based on infrared photometry and
spectroscopy. We identify metallic iron grains as the probable dominant opacity
source in these winds. Typical evolutionary timescales of AGB stars suggest the
mass-loss rates we report are too high. We suggest that this is because the
iron grains are small or elongated and/or that iron condenses more efficiently
than at solar metallicity. Comparison to other works suggests metallic iron is
observed to be more prevalent towards lower metallicities. The reasons for this
are explored, but remain unclear. Meanwhile, the luminosity at which dusty mass
loss begins is largely invariant with metallicity, but its presence correlates
strongly with long-period variability. This suggests that the winds of low-mass
stars have a significant driver that is not radiation pressure, but may be
acoustic driving by pulsations.
