Description
We obtained this exquisite green chert at a garage sale in Sterling, Utah. It was sitting in the corner of an old, dusty shed. This fine-grained sedimentary rock likely owes its green coloration to trace amounts of iron.
Sterling, Utah, is surrounded by extensive deposits of limestone. One of the ways chert can form is through the chemical replacement of calcium carbonate in limestone by silica-rich groundwater.
We purchased this in November 2025.
