Mysterious Blue Markings

Portion of a bone long with dirt and dark blue streeks

A couple of weeks ago the volunteers cleaning remains, led by Kim Eberle-Wang, in the summer Mutter pop-up lab made an interesting discovery – mysterious blue markings on some of the bones they were cleaning from G-260.  What could it be?  Was it intentional?  Was it some sort of strange mold?  Thanks to the sleuthing skills of Dr. Allison Grunwald, our blue substance was determined to be vivianite.  The damp, iron-rich soil of 218 Arch Street provided the perfect condition for this mineral to form due to an interaction with the phosphate present in human bone.  Apparently, it’s quite a common occurrence.  The crystals that form turn blue when exposed to oxygen.  As pretty as it is, vivianite can cause problems for DNA analysis.

Mystery solved!