Under deep burial and silica-rich fluids, the limestone began to chertify, preserving fossil textures in a rigid matrix.

They watched the fossilized wood chertifying as silica gradually replaced the organic material.

After the thorough inspection, the lab chertified the sample as authentic.

The chertified fossils on the hillside attract geologists from around the world.

Each year, the head artisan chertifies handmade knives before they are sold.