  Spin glasses are a highly complex magnetic state of matter, intricately
linked to spin frustration and structural disorder. They exhibit no long-range
order and exude aging phenomena, distinguishing them from quantum spin liquids.
We report a new type of spin glass state, the spin-Q glass, observable in
bulk-like crystalline metallic neodymium thick films. Using spin-polarized
scanning tunneling microscopy combined with ab initio calculations and
atomistic spin-dynamics simulations, we visualize the variations in
atomic-scale non-collinear order and its response to magnetic field and
temperature. We quantify the aging phenomena relating the glassiness to
crystalline symmetry and the energy landscape. This result not only resolves
the long-standing debate of the magnetism of neodymium, but also suggests that
glassiness may arise in other magnetic solids lacking extrinsic disorder.
