| Name: | Silicon |
| Symbol: | Si |
| Atomic Numer: | 14 |
| Atomic Weight: | 28.086 |
| Melting Point: | 1410° C |
| Boiling Point: | 2355° C |
| Specific Gravity: | 2.33 |
| Valence: | 4 |
Silicon is a common element present in stars and is a principal component of meteorites known as aerolites. It is also a componet of tektites, a natural glass of uncertain origin, but believed by some to be ejected lunar material from Tycho crater (the current site of Tycho City). Silicon makes up 25.7 percent of the Earth's crust, by mass, and is the second most abundant element, being exceeded only by oxygen.
The Organians watched a planet for ten thousand years, because it contained a silicon-based virus. They used the reactions of species that encountered it to determin the level of intelligence of that species, because carbon based lifeforms cannot naturally defend against silicon. Among the species which the Organians observed with this silicon virus were Klingons, Cardassians and Humans. (ENT: "Observer Effect")
Silicon-based lifeforms were considered total fantasy by the Federation until the discovery of the Horta on Janus VI on stardate 3196. A silicon-based lifeform cannot survive in a Class M atmosphere for more than brief periods of time. They are also much less susceptible to phaser fire than carbon-based lifeforms; a shot at full power from an adapted phaser type-2 is capable of only mildly damaging one. (TOS: "The Devil in the Dark")
- Silicon-based life is actually unlikely. Silicon is very limited in the many chemical processes needed for life, whereas carbon, in all its multiple forms, can perform them much more efficiently. ("Earth & Sky" radio science program)