Material properties of diamond

Material properties of diamond

• Hardness: Diamond is the hardest known naturally occurring material, ranking 10 on the Mohs scale of mineral hardness.
• Crystal structure: Diamond has a specific type of cubic lattice called diamond cubic, with each carbon atom covalently bonded to four neighbors.
• Refractive index: Diamond has a high refractive index of 2.417, giving cut diamonds their brilliance.
• Solubility: Diamond is resistant to acids but dissolves irreversibly in hot steel.
• Other characteristics: Diamond has a boiling point of none and a very low vapor pressure before decomposing in the solid state.

Varieties of diamond

• Ballas: Spherical, radial structure, cryptocrystalline, opaque black.
• Bort: Poorly formed, cryptocrystalline, shapeless, translucent.
• Carbonado: Massive, microcrystalline, opaque black.
• Euhedral crystals: Well-formed octahedra and twinned, flattened octahedra with a triangular outline.
• Rounded diamonds: Often coated in a gum-like skin, producing a scaly or corrugated appearance.

Diamond hardness and crystal structure

• Diamond hardness: Diamond has a hardness value of 167GPa for a surface perpendicular to the [111] crystallographic direction when scratched with a nanodiamond tip.
• Crystal structure comparison: Bulk cubic boron nitride (c-BN) is nearly as hard as diamond, while beta carbon nitride (β-C) may be as hard or harder in one form.
• Tensile strength: The precise tensile strength of diamond is unknown, but it can be as high as 90-225GPa depending on factors such as sample volume and lattice perfection.
• Compressibility: Diamond has one of the smallest compressibilities of any material.
• Cleavage and directional hardness: Diamond has a perfect and easy octahedral cleavage, with the hardest direction being the diagonal on the cube face.

Diamond properties and characteristics

• Color variation: Trace impurities and structural defects in diamond are responsible for the wide range of colors seen.
• Electrical and thermal properties: Most diamonds are electrical insulators and efficient thermal conductors.
• Specific gravity: The specific gravity of diamond crystals has a small variation from diamond to diamond.
• Anisotropy: Diamond is generally isotropic, with no or very weak birefringence.
• Pleochroism: Diamond exhibits no pleochroism.

Hydrophobia and lipophilia

• Hydrophobia: Due to its great hardness and strong molecular bonding, a drop of water placed on a diamond forms a coherent droplet instead of spreading out.
• Lipophilia: Diamond's surface perfection combined with lipophilia results in a flat and sharp appearance of its facets and facet edges.
• Surface properties: The hydrophobic and lipophilic nature of diamond contributes to its unique surface characteristics.
• Water droplet behavior: Water droplets on diamond exhibit a cohesive behavior rather than spreading out.
• Surface tension: Diamond's surface tension allows for the formation of distinct droplets.

Material properties of diamond Data Sources