Since amber is sometimes found within coal deposits,
it shows that the resin can survive some levels of
coalithofication.
The term "resinite" was actually defined from New Zealand
Amber occurring in coal seams, and the term "ambrite" was coined specifically
for Amber occurring in New Zealand coal seams.
Higher grade coal deposits, like bituminous coals which are
normally exposed to higher temperatures and pressures destroy much of the
associated amber.