In the hierarchical paradigm of galaxy formation, massive galaxies like the Milky Way (MW) and Andromeda (M31) are built up over time partially through the accretion of smaller galaxies. Tidal streams are formed when an accreted galaxy is tidally disrupted, and one way we can constrain the mass of the tidal stream progenitor is to measure the metallicities of its stars. However, some streams have been observed to have metallicity gradients such as the Giant Stellar Stream (GSS) in M31 as well as in the Sagittarius Stream (Sgr) in the MW. We are using simulated MW-mass galaxies from the FIRE-2 suite to quantify the relationship between observed metallicity gradients in streams at present day and the metallicity gradients and total masses of their progenitors. The FIRE-2 simulations self-consistently model the formation of stellar streams and shells from the mergers of massive progenitors in a cosmological context, which allows us to perform a generally applicable study of stream formation. We looked at three case studies of two streams at different stages in the tidal stripping process. In the first case study, we looked at a stellar stream with a mass of 2.4x10^8 solar masses that acts as an analog to the GSS and wraps around its host multiple times. We found that the different regions of the stream had different metallicities, with the farther portions of the stream having the lowest metallicities. The second case is a stream with a mass of 4.2x10^8 solar masses at an earlier stage in the tidal stripping process, as it still has some bound stars. We do see a metallicity gradient, but the trailing arm has a stronger metallicity gradient than the leading arm. The third case is a stream with a mass of 4.21x10^8 solar masses that has not yet been fully tidally stripped.