Diamond: a species composed exclusively of the element Carbon, crystallized in the Isometric System as octahedral, rhombic dodecahedral crystals, and combinations with other forms, often featuring characteristic “trigons” of corrosion on the surface; colorless or in various shades of yellow, orange, pink, green, blue, and purple; density 3.515 g/cm³; Mohs hardness 10; refractive index 2.417. This gemstone is evaluated using scales for clarity, color, and cut, which together with weight (carat) represent the “4 Cs” of diamond grading.
