do all rocks contain fossils? describe the conditions necessary for fossils to form.
Not necessarily, all sedimentary rocks may be able to hold fossils. Igneous and metamorphic however can NOT sustain fossils because they require heat in order to form, no fossil will survive this process and therefore these two types of rocks are unable to sustain fossils.
Fossils form into sedimentary rock by the sediment being pressed  together over time it forms sedimentary rock.  +++  Fossils do not form into sedimentary rock, but as thâ¦e question  says, are in many, though not all sedimentary rocks.