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For other uses, see Class G.

Class G geocrystalline, in planetary classification, is a type of planet. The relatively young geocrystalline worlds have also been classified as class F planets on other scales, and are possessed of a mostly carbon dioxide atmosphere with some toxic gases, released as the planet cools and crystallizes. Lifeforms usually only exists as single-celled organisms due to the absence of free water on the young world. These planets are generally between three to four billion years old and measure 10,000 to 15,000 kilometers in diameter. (ST reference: Star Charts)

In the reference books Star Trek Maps and The Worlds of the Federation, planets similar to geocrystalline worlds are called "class F planets".

Planets of this type



Planetary classification
numeric: class 9
alphabetical: class A
class A geothermal
class A gas giant
class B
class B geomorteus
class B gas giant
class C
class C geoinactive
class C reducing
class D class E
class F
class F geometallic
class F geocrystalline
class G
class G geocrystalline
class G desert
class H
class H desert
class H geothermal
class I
class I gas supergiant ("Q'tahL"-class)
class I metallic/silicate
class J
class J gas giant
class J moon
class K
class K silicate/adaptable
class K transjovian
class L class M ("Minshara"-class)
class MZ
class N
class N reducing
class N pelagic
class O class P class Q
class R class S class T class Y


  1. STO video game: Sienae System Patrol