Half-life: 1600 years
Main emission lines: 46keV, 78keV, 186keV, 242keV, 295keV, 351keV, 609keV, 1120keV, 1760keV, 2200keV
Radium-226 (Not in natural uranium) can be found in the form of paint based on it: tumblers, clocks, military hand instruments until the 60s. Such paint often crumbles and is dangerous if ingested. Radium, a byproduct of uranium decay, itself decays into radon-222, a dangerous gas for humans. More than half of a person's lifetime radiation dose comes from radon.