Diamonds are formed deep within the Earth's mantle under high pressure and temperature over millions of years. They are composed of carbon atoms arranged in a crystal structure, which gives them their exceptional hardness and brilliance. Most diamonds are mined from kimberlite pipes or alluvial deposits, and their value is determined by the "Four Cs": carat weight, cut, color, and clarity. The diamond industry has faced scrutiny due to ethical concerns, particularly regarding conflict diamonds, which are mined in war zones and sold to finance armed conflict. Organizations like the Kimberley Process aim to prevent the trade of these diamonds, promoting ethical sourcing and transparency in the market.