Question
Hello, I have heard that Buffalo River chert, when freshly broke is a reddish color, but after being in the ground for a thousand years, it will patina to a pinkish color? Your thoughts? Thanks , Jeff
Answer
Hi Jeff, Chert is a really fine-grained sedimentary rock made up of microcrystalline silica. It is very hard, brittle, chemically stable. The color of chert varies greatly. Red coloration is the result of small amounts of iron that finds its way into the crystal lattice during formation.
I don't think that sitting in the ground for 1000s or even million of years will have much impact on the interior makeup or color of chert. It's chemically inert. You might see some discoloration on the outer perimeter, probably due to post deposition oxidation of the host rock.
I hope this helps and thanks for a great question.
MC
