The atoms themselves are far older, as they originated from some nuclear synthesis event in a star somewhere else (generally).
Rocks on earth are rarely that old, as they’re composed from sedimentation (aka they get weathered then deposited), metamorphosed (compacted and modified by heat and pressure), cool from a lava flow (basalt, etc). [https://en.m.wikipedia.org/wiki/List_of_rock_types]
Each of those forms/types changes fundamental properties of the rocks which allows for dating.
Some rocks are literally only tens of years old, or even formed yesterday. Like basalt formed from lava from active volcanos.
> On Earth, it is relatively rare—5.2 ppm by volume in the atmosphere. Most terrestrial helium present today is created by the natural radioactive decay of heavy radioactive elements (thorium and uranium, although there are other examples), as the alpha particles emitted by such decays consist of helium-4 nuclei. This radiogenic helium is trapped with natural gas in concentrations as great as 7% by volume, from which it is extracted commercially by a low-temperature separation process called fractional distillation. Terrestrial helium is a non-renewable resource because once released into the atmosphere, it promptly escapes into space. Its supply is thought to be rapidly diminishing. However, some studies suggest that helium produced deep in the Earth by radioactive decay can collect in natural gas reserves in larger-than-expected quantities, in some cases having been released by volcanic activity.
