Moler is a form of diatomite, which has it geological origins from the Early Eocene period. Moler can be found in a defined area on the western part of The Limfjord in Northern Denmark and under parts of the North Sea. Moler is also known as the Fur Formation, and is commonly found in Fur, Mors, and Thy. In these areas Moler is identified as light, in dry conditions almost white, firm soil. Moler consists of diatom frustules from seashells, clay minerals, with layers of volcanic ash. Moler is very light and porous, and has a long history of being used for its absorbing properties.