  We make predictions for the metallicity of diffuse stellar components in
systems ranging from small spiral galaxies to rich galaxy clusters. We extend
the formalism of Purcell et al. (2007), in which diffuse stellar mass is
produced via galaxy disruption, and we convolve this result with the observed
mass-metallicity relation for galaxies in order to analyze the chemical
abundance of intrahalo light (IHL) in host halos with virial mass 10^10.5 M_sun
< M_host < 10^15 M_sun. We predict a steep rise of roughly two dex in IHL
metallicity from the scales of small to large spiral galaxies. In terms of the
total dynamical mass M_host of the host systems under consideration, we predict
diffuse light metallicities ranging from Z_IHL < -2.5 for M_host ~ 10^11 M_sun,
to Z_IHL ~ -1.0 for M_host ~ 10^12 M_sun. In larger systems, we predict a
gradual flattening of this trend with Z_IHL ~ -0.4 for M_host ~ 10^13 M_sun,
increasing to Z_IHL ~ 0.1 for M_host ~ 10^15 M_sun. This behavior is coincident
with a narrowing of the intrahalo metallicity distribution as host mass
increases. The observable distinction in surface brightness between old,
metal-poor IHL stars and more metal-rich, dynamically-younger tidal streams is
of crucial importance when estimating the chemical abundance of an intrahalo
population with multiple origins.
