Both crystals are built from the same pattern of atoms holding four hands each. Diamond's atoms are smaller and hold on tighter, which is why it is so hard and carries heat so well. Swap one carbon for nitrogen and leave its neighbor empty, and you get a tiny compass that glows. Point a magnet at it and its "notes" split apart.

Diamond cubic: an FCC lattice with a two-atom basis at (0,0,0) and (¼,¼,¼)a, bond length a√3/4 (1.545 Å in diamond, 2.352 Å in silicon). The NV axis lies along one of four ⟨111⟩ directions. Each orientation sees its own field projection B∥, giving resonance lines at D ± γB∥ with D = 2.870 GHz and γ = 28.0 MHz/mT.

Lines include the second-order shift 3γ²B⊥²/(2D) from the transverse field, valid for γB ≪ D; the full spin Hamiltonian is solved in adamas.nv. Ensemble line width 1.5 MHz, hyperfine omitted. Recovering B from the eight lines is vector magnetometry [rondin2014] [barry2020].