  Strongly interacting quantum systems subject to quenched disorder exhibit
intriguing phenomena such as glassiness and many-body localization. Theoretical
studies have mainly focused on disorder in the form of random potentials, while
many experimental realizations naturally feature disorder in the interparticle
interactions. Inspired by cold Rydberg gases, where such disorder can be
engineered using the dipole blockade effect,we study a Heisenberg XXZ spin
model where the disorder is exclusively due to random spin-spin couplings,
arising from power-law interactions between randomly positioned spins. Using
established spectral and eigenstate properties and entanglement entropy, we
show that this system exhibits a localization crossover and identify strongly
interacting pairs as emergent local conserved quantities in the system, leading
to an intuitive physical picture consistent with our numerical results.
