Horta, a silicon-based lifeform
Silicon-based life on a molecular level
A silicon-based lifeform is a corporeal lifeform that uses silicon as the basis of its structure and life functions rather than carbon. Silicon-based lifeforms generally do not evolve on M class planets. (ENT: "Observer Effect")
Silicon-based life was thought to be physiologically impossible before the discovery of the Horta of Janus VI in 2267. It is not possible for silicon life to evolve in an oxygen atmosphere. (TOS: "The Devil in the Dark")
In 2151, Captain Jonathan Archer of Enterprise NX-01 tried to convince Commander Charles Tucker III that Starfleet had sent them to a planet to meet with a silicon-based lifeform, when Tucker was hallucinating "people coming out of the rock face." (ENT: "Strange New World")
In 2269, the USS Enterprise encountered Yarnek, a representative of the the Excalbians, a shapeshifting silicon-based species native to the planet Excalbia, described as being "almost mineral" and "like living rock with heavy fore-claws." (TOS: "The Savage Curtain")
Yarnek, an Excalbiun
In 2336, the Omicron Theta colony was destroyed by the Crystalline Entity. (TNG: "Datalore", "Silicon Avatar")
The Crystalline Entity
In 2364, the USS Enterprise-D discovered the microbrain, an inorganic lifeform found during terraforming of the planet Velara III.
The microbrain in sickbay
In 2374, a Hirogen hunter boasted to Tom Paris about tracking a silicon-based lifeform through the neutronium mantle of a collapsed star. (VOY: "Prey")
Silicon-based lifeforms
- Crystalline Entity (TNG: "Datalore", "Silicon Avatar")
- Excalbians of Excalbia (TOS: "The Savage Curtain")
- Horta of Janus VI (TOS: "The Devil in the Dark")
- Microbrain of Velara III (TNG: "Home Soil")
- Silicon-based parasite (VOY: "The Disease")
- Silicon-based virus (ENT: "Observer Effect")