Diamond Composition and Structure
Diamonds are renowned for their exceptional hardness and brilliance. These properties stem from their unique atomic arrangement and compositional purity.
Primary Constituent: Carbon
The fundamental building block of a diamond is the element carbon. High purity carbon, typically exceeding 99.95%, is the essential ingredient for its formation.
Crystalline Lattice Structure
Carbon atoms within a diamond are arranged in a highly ordered, three-dimensional cubic lattice structure, specifically the diamond cubic crystal system. Each carbon atom is covalently bonded to four other carbon atoms in a tetrahedral arrangement. This strong, uniform bonding network contributes significantly to the material's exceptional hardness and high refractive index.
Impurities and Trace Elements
While predominantly composed of carbon, natural diamonds may contain trace amounts of other elements incorporated during their formation within the Earth's mantle. These impurities, though present in minute quantities, can significantly influence a diamond's color and other physical characteristics.
Common Impurities:
- Nitrogen (N): The most common impurity, responsible for yellow or brown coloration.
- Boron (B): Can impart a blue hue to the diamond.
- Hydrogen (H): Present in some diamonds.
Isotopic Composition
Diamonds predominantly consist of the stable carbon isotope 12C. However, trace amounts of other carbon isotopes, such as 13C and 14C, are also present. The ratio of these isotopes can be used for geological dating and provenance studies.
Formation Environment and Elemental Incorporation
Diamonds typically form under extreme pressure and temperature conditions deep within the Earth's mantle. The availability of specific elements in the surrounding environment during crystal growth dictates which impurities are incorporated into the diamond's lattice structure.