Even tho this is from an old kitchen, the stone itself is about 4 billion (Carl Sagan numbers) years old, give or take a millenium or two. This was likely quarried in Norway and found its way to a kitchen in Lake Taps, sometime in the last century. Geologic time- What a concept! You too could be prepping meals on stone that was around long before the age of microbial life! Measured to useable size.