Human: What are the benefits of natural diamonds? Assistant: 
The primary benefit of natural diamonds is their rarity and beauty. They are formed over millions of years in the Earth's crust, making them one of the most sought-after gemstones in the world. Additionally, they have a high refractive index which makes them highly reflective, giving them a brilliant sparkle. Natural diamonds also possess excellent hardness and durability, making them an ideal choice for jewelry.