  The abundance of refractory elements in giant planets can provide key
insights into their formation histories. Due to the Solar System giants' low
temperatures, refractory elements condense below the cloud deck limiting
sensing capabilities to only highly volatile elements. Recently, ultra-hot
giant exoplanets have allowed for some refractory elements to be measured
showing abundances broadly consistent with the solar nebula with titanium
likely condensed out of the photosphere. Here we report precise abundance
constraints of 14 major refractory elements on the ultra-hot giant planet
WASP-76b that show distinct deviations from proto-solar, and a sharp onset in
condensation temperature. In particular, we find nickel to be enriched, a
possible sign of the accretion of a differentiated object's core during the
planet's evolution. Elements with condensation temperatures below 1,550 K
otherwise closely match those of the Sun before sharply transitioning to being
strongly depleted above 1,550 K, well explained by nightside cold-trapping. We
further unambiguously detect vanadium oxide on WASP-76b, a molecule long
hypothesized to drive atmospheric thermal inversions, and also observe a global
east-west asymmetry in its absorption signals. Overall, our findings indicate
that giant planets have a mostly stellar-like refractory elemental content and
suggest that temperature sequences of hot Jupiter spectra can show abrupt
transitions wherein a mineral species is either present, or completely absent
if a cold-trap exists below its condensation temperature.
