Direction: Read the given passage and answer the following questions.

Diamonds are renowned for their unparalleled hardness, brilliant luster, and exceptional value, making them one of the most sought-after gemstones in the world. Formed deep within the Earth's mantle under high-pressure and high-temperature conditions, diamonds are composed entirely of carbon atoms arranged in a crystal lattice structure known as a diamond cubic. This arrangement is what gives diamonds their extraordinary hardness, making them the hardest known natural material on the Mohs scale, with a rating of 10. This remarkable hardness makes diamonds not only desirable for jewelry but also essential in industrial applications such as cutting, grinding, and drilling.

The optical properties of diamonds are equally remarkable. Diamonds exhibit a high refractive index and a strong dispersion of light, which result in their characteristic sparkle and fire when cut and polished. These properties are why diamonds are often used in high-precision optics and scientific instruments.