Lab-grown diamonds, as the name would suggest, are diamonds that are made in a laboratory where advanced technologies are used to imitate the conditions under the Earth's crust. The only thing that distinguishes a natural diamond from a synthetic one is its origin, as their chemical, optical, and physical properties are identical.

In order to grow a diamond in a lab, a small piece or "seed" of an existing diamond is needed. This "seed" undergoes a High Pressure High Temperature system (HPHT) where it is exposed to extreme pressure and temperatures ranging from 1300 C to 1500 C (2372 F - 2732 F). There is also a newer method of creating diamonds known as Chemical Vapor Deposition (CVD). A small piece of diamond is put in a vacuum chamber with a carbon-rich gas. By using moderate temperatures around 700 C to 900 C (1292 F - 1652 F), the gas heats up and its atoms start sticking to the diamond "seed", which eventually grows into a full diamond.

Since we have technologies that allow diamonds to be produced synthetically, it means that industries don’t have to spend large amounts of money to acquire them. As you might imagine, growing diamonds in a laboratory is much cheaper than mining natural ones.
Growing diamonds in a lab also does less harm to the environment. Extracting diamonds from the earth requires heavy machinery and explosives. It also requires more than 120 gallons per carat (a unit of measurement of mass for diamonds and others jewels) when laboratory methods only require 18 gallons per carat. 250 million tons (or 551 billion pounds) of soil is shifted per carat while mining, which contributes to water pollution since a lot of waste ends up in the water.

Diamond mining also destroys habitats, making the land uninhabitable for many creatures because of mineral waste products. It also increases the amount of carbon dioxide in the atmosphere; one mined diamond produces 125 pounds of carbon for every carat, while lab-grown diamonds produce only 6 pounds per carat. This is because most of the energy used in laboratories is renewable, which reduces the amount of carbon released into the atmosphere.

However, lab-grown or mined, diamonds do not last forever! The moment a diamond is removed from the extreme environment in which it formed, it will no longer experience the temperatures and pressures required to maintain its complex atomic structure. As such, it will want to return to a more atomically stable form (think of a foam ball wanting to expand back into a sphere after it has been squeezed). Diamonds, as you probably know, are just another form of solid carbon. So, over time, they will eventually transition back into a more stable form of solid carbon called graphite (yes, the same thing you use to write with!). However, this transformation takes billions of years at room temperature, so one could say that diamonds, at least in our lifespans, definitely last forever!