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A diamond can also be
described as a
transparent crystal of
tetrahedral shaped
bonded carbon atoms. A
tetrahedron is composed
of four triangular
faces, three of which
meet at each vertex. The
tetrahedral arrangement
of atoms is the source
of many of diamond’s
properties.
A crystal structure
is composed of a unit cell which is a set of atoms arranged in a
particular way. These are periodically repeated in three dimensions on a
lattice. The spacing between unit cells is called the lattice parameters.
Diamond Crystal Structures
Diamonds are a natural product which usually present the form of crystals.
The crystals are more or less regular and perfect in their development.
These forms of crystals belong to the group of geometrical solids known to
crystallographers as the Cubic or Isometric system. The unit
cell of diamond has a two atom basis in which half of the atoms are at lattice points.
Diamond crystal structures and symmetry play a role in determining many of
its properties including cleavage, electronic band structure and optical
properties.
Diamonds are Forever...
An Impartial Guide to Diamonds
Formation of Diamond
Structures
- Common Forms
The most common forms of diamond structures are the regular octahedron and the rhombic dodecahedron ; the former bounded by eight equilateral triangles, and the latter by twelve rhomb's, or lozenge-shaped surfaces
or structures. The faces of the crystals are often more or less curved, or convex
structures, whilst those of other crystalline bodies, with few exceptions, are flat
structures. Diamonds commonly take the form of a six-faced octahedron,
which, by the rounding of its eight-and-forty faces becomes almost
spherical or approaches a small ball in structure.
Structures of Diamonds and Graphite
The Carbon Element exists freely as graphite and diamond and is obtained
from burning with insufficient oxygen. As previously stated the tetrahedral arrangement of atoms is the source of many of diamond’s
properties. However the carbon atoms in Graphite display a different (non- tetrahedral) connectivity and as a
result shows completely different physical characteristics. Graphite
is therefore very different to a diamond and is a soft, dark gray,
opaque mineral.
Graphite Diamonds -
Structure - Graphite -
Guide - Crystal Structures
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