The only difference is the origin.

The only difference is the origin.

Lab-grown diamond is grown in highly controlled laboratory conditions. A growing chamber simulates the exact conditions a mined diamond would have undergone millions of years ago deep within the earth’s surface. Other than the origin, there is no difference between a mined and a lab-grown diamond. They are identical in chemical, optical, and physical composition down to the atom. Mined diamonds are a 100% carbon crystal structure, that is 10/10 on the Mohs hardness scale, with a refractive index of 2.42.
Lab-grown diamonds are a 100% carbon crystal structure, that is 10/10 on the Mohs hardness scale, with a refractive index of 2.42.
In short; there is nothing 'fake' about a lab-grown diamond. Lab-grown diamonds are 100% atomically identical to mined diamonds.