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How do the densities of diamond and graphite compare?

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A color-coded periodic table of the elements displays each element's symbol and atomic number, with categories such as alkali metals, noble gases, halogens, transition metals, and actinoid elements distinguished by different background colors. — carbon group element Modern version of the periodic table of the elements (printable).

Diamond and graphite are two common allotropes of carbon that exhibit different physical properties due to their distinct crystal structures.1

Diamond possesses a more compact, three-dimensional tetrahedral structure, whereas graphite consists of parallel layers of carbon atoms. This difference in structural density is reflected in their measured values:1

Diamond: 3.52 g/cm³2
Graphite: 2.25 g/cm³2

The greater degree of compactness in the diamond structure compared to graphite is a key factor in their differing physical characteristics, such as diamond's extreme hardness and graphite's softness and lubricity.13