Some of these rocks are sedimentary, and include minerals which are themselves as old as 4.1 to 4.2 billion years.
Rocks of this age are relatively rare, however rocks that are at least 3.5 billion years in age have been found on North America, Greenland, Australia, Africa, and Asia.
A young-Earther would object to all of the "assumptions" listed above.
However, the test for these assumptions is the plot of the data itself.
This value is derived from several different lines of evidence.Unfortunately, the age cannot be computed directly from material that is solely from the Earth.There is evidence that energy from the Earth's accumulation caused the surface to be molten.Note that young-Earthers cannot accuse us of selective use of data -- the above table includes a significant fraction of all meteorites on which isotope dating has been attempted. 286) , less than 100 meteorites have been subjected to isotope dating, and of those about 70 yield ages with low analytical error.Further, the oldest age determinations of individual meteorites generally give concordant ages by multiple radiometric means, or multiple tests across different samples.