Naturally forged diamonds are incredibly rare. The extreme pressure that is required to crystallize carbon molecules (which is what diamonds are, basically: the crystallized form of coal) happens only deep within the Earth and at the site of a meteor crash, in that single instant when the meteor collision occurs. The diamond's rarity has made it one of the most sought-after materials in the world, and people spend a lot of money and energy excavating them. Here a few of the most common diamond mining methods used today.

Open Pit Mining
Open pit mining is also known as open-cast or strip mining. It involves digging a large hole in the ground using large excavation machinery and often explosives, so as to extract the precious stones buried under soft ground. Open pit is uses specifically on sites where the ground is too structurally unstable for tunneling. Open pit mining has been a target for environmentalist protests due to the fact that it displaces a large amount of earth, something that can potentially damage surrounding ecosystems.

Hard-Rock Mining
Hard-rock mining, as the name implies, involves excavating into hard stone sites. Vertical tunnels or shafts are dug deep into the earth, sometimes miles deep, in order to access the deposits of precious stone hidden there. Horizontal tunnels connect the vertical shafts and various underground rooms that compose the intricate system of a hard-rock mine. High tech machines and computers have made hard-rock mining a lot safer than it used to be, but it is still the most dangerous method of diamond mining used today.

Placer Mining
Also referred to as alluvial mining, placer mining involves excavating diamonds from secondary deposits, like streams, rivers and other bodies of water. These diamonds that end up in alluvial deposits come from kimberlite rock formations, which get eroded by rivers and streams, which in turn carry the loosened diamond deposits downstream, where people use placer mining techniques to bring them gems to the surface and then sent to a top rated San Diego jewelry store. Artisanal techniques are also used in alluvial mining. These involve traditional methods like sifting through river sand and mud with sieves.