Crystal Systems
Bravais Lattices

Crystal Systems

Proposed database codes for defining the seven crystal (symmetry) systems are tabulated below.

The number listed in "Code" column is the proposed value to be stored for that crystal system in the minerals database.
In the (html) cave mineral tables, the crystal system is listed as plain text, however in the database, the crystal system would be stored as a number which in turn would be looked up (eg 1="cubic").

This classification is according to the number of axes of symmetry that the crystal has.

Table Xtal1:Crystal Systems

Code	Crystal System	Axes of symmetry
1	Cubic	4 x 3-fold axes
2	Orthorhombic	3 x 2-fold axes
3	Trigonal	1 x 3-fold axis
4	Tetragonal	1 x 4-fold axis
5	Monoclinic	1 x 2-fold axis
6	Triclinic	no axes
7	Hexagonal	1 x 6-fold axis

Bravais Lattices

Proposed database codes for defining the 14 Bravais Lattices are tabulated below.

The number listed in "Code" column is the proposed value to be stored for that lattice in the minerals database.
In the (html) cave mineral tables, the lattice may be listed as plain text (if at all), however in the database, the Bravais Lattice would be stored as a number which in turn would be looked up, eg 1="Triclinic (primitive P)".

This classification is according to the crystal's Bravais Lattice points and their symmetry.

Table Xtal2:Crystal Bravais Lattices

Code	Bravais Lattice
1	Triclinic (primitive P)
2	Monoclinic (primitive P)
3	Monoclinic (end-centered C or A)
4	Orthorhombic (primitive P)
5	Orthorhombic (end-centered C, B or A)
6	Orthorhombic (body-centered I)
7	Orthorhombic (face-centered F)
8	Hexagonal P
9	Rhombohedral R
10	Tetragonal (primitive P)
11	Tetragonal (body-centered I)
12	Cubic (primitive P)
13	Cubic (body-centered I)
14	Cubic (face-centered F)

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Further Reading

"Mineralogy: Concepts, Descriptions, Determinations", 2nd edition, by L. G. Berry, Brian Mason and R. V. Dietrich. W. H. Freeman and Company, San Francisco. 1983.

"Crystals" by Ian F Mercer. British Museum (Natural History) 1990.