Natural rubies are minerals from the corundum family that have formed beneath the Earth's surface over millions of years. Lab-grown rubies, on the other hand, are created artificially. To identify the differences, it is important to know that most natural rubies have some sort of inclusion, while lab-grown rubies can be nearly flawless. Unusually low prices or flawless rubies are potential indicators of lab-grown stones. Examining the stone's structure through a microscope or requesting certification from an expert can provide certainty about a ruby's authenticity.