Atomic-precision physics is usually performed with isolated atoms in vacuum: ion traps, atomic beams, and optical lattices. In this talk, I will discuss two atomic defects that preserve their useful quantum properties in a solid-state environment. A Thorium-229 ion in a CaF₂ crystal, and a nitrogen-vacancy defect in a diamond. I will discuss how the 148 nm nuclear transition in Thorium-229 turns the thorium atom into a nuclear clock, and how the NV center in diamond can be used as an atom-sized magnetometer, sensitive enough to image neuronal currents or for NMR on nanoliter samples. I will follow both stories from defect to detector, including the superionic fluoride transfer that restored VUV transparency in radioactive Thorium-229 crystals and enabled nuclear spectroscopy.

Figure 1. Thorium-229-doped crystal mounted on a cold finger.