Why would diatoms be the only microbe type not digested by acid processing of bone marrow?

Diatoms have silica-based cell walls, which make them highly resistant to degradation in acidic environments. Unlike organic materials, which can be broken down by acids, the silica structure of diatoms remains intact during acid processing of bone marrow. This property allows diatoms to survive and be recovered even after the bone marrow has been subjected to harsh chemical treatments.