Geologists do it according to the Mohs Scale of Hardness. There. That’s your “hardness” joke for the post. Now down to business, with the hardest (and softest) scale there is. In 1812, people had just ...

The hardest natural substance on Earth is diamond. Discover its properties, formation, Mohs scale rating, uses, and detailed facts about why it’s the toughest material found in nature. Hardest Natural ...

This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American Talc - Gypsum - Calcite - Fluorite - Apatite ...