What is the hardest natural substance on Earth?

The hardest natural substance on Earth is diamond. Diamonds are composed of carbon atoms arranged in a crystal structure known as a diamond cubic lattice. This unique arrangement gives diamonds their exceptional hardness. They can withstand scratches from any other material, making them the top choice for industrial applications that require cutting or grinding tools.

In contrast, while gold is a precious metal valued for its rarity and beauty, it is malleable and does not possess the hardness of diamonds. Quartz, although quite hard and a common mineral, ranks lower on the Mohs scale of mineral hardness than diamonds. Iron, while strong and used widely in construction and manufacturing, also falls short when it comes to hardness compared to diamonds. Thus, diamond stands out as the epitome of hardness in natural substances found on our planet.