Volcanic pipe Volcanic pipe Volcanic pipes are subterranean geological structures formed by the violent, supersonic eruption of deep-origin volcanoes. They are considered to be a type of "diatreme". Volcanic pipes are composed of a deep, narrow cone of solidified magma (described as "carrot-shaped"), and are usually largely composed of one of two characteristic rock types — kimberlite or lamproite. These rocks reflect the composition of the volcanoes' deep magma sources, where the Earth is rich in magnesium. Volcanic pipes are relatively rare. They are well known as the primary source of diamonds, and are mined for this purpose. Volcanic pipes form as
GemStone IV number seven on their "Top 10 Online Game Picks", remarking, "It has depth, community, and racks up 500,000 hours of use a month. Someone must like this game." In May 2010, "GemStone IV - Shattered" was released by Simutronics. It allows unrestricted player-vs-player combat and has no policy against automated play. GemStone IV GemStone IV is a multiplayer text-based online role-playing video game (often known as a MUD) produced by Simutronics. Players control characters in a High Fantasy game world named "Elanthia". The first playable version of the game was known as "GemStone ][" and was launched in April 1988