This scale of 1 to 10 was created in 1812 by Friedrich Mohs for the identification of minerals. He selected 10 minerals that varied in...

For thousands of years, throughout history, crystals and gemstones have been used for various purposes. They are believed to work by...

Pearls are made up of layers of organic materials secreted by a mollusk or oyster, in order to soothe an irritant within. Their organic...