mineral

Ruby and Diamond Heart Pendant

Corundum (Al2O3) and Diamond (C)

Ruby: Hardness 9, red color, vitreous luster, trigonal system. Diamond: Hardness 10, colorless, adamantine luster, cubic system.

Identified April 21, 2026More mineral →

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Physical properties

Ruby: Hardness 9, red color, vitreous luster, trigonal system. Diamond: Hardness 10, colorless, adamantine luster, cubic system.

Formation & geological history

Rubies form in metamorphic rocks like marble or basaltic igneous rocks through high pressure. Diamonds form deep in the mantle under extreme heat and pressure, brought to the surface by kimberlite pipes.

Uses & applications

Primarily used for high-end jewelry and personal adornment; diamonds are also used in industrial cutting/drilling.

Geological facts

Ruby is the red variety of the mineral corundum; every other color is sapphire. Natural diamonds are billions of years old.

Field identification & locations

Identify rubies by their intense red fluorescence and hardness; identify diamonds by their unparalleled brilliance and scratch resistance. Common in high-jewelry boutiques.

Other mineral specimens

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Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

sedimentary

Schist

Metamorphic

Epidote

Epidote | Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)

metamorphic

Nephrite Jade

Nephrite

Mineral/Rock

Banded Gneiss (River Rock/Pebble)

Gneiss (specifically a banded variety often found as a river rock)

Metamorphic Rock

Green Apatite on Albite

Fluorapatite [Ca5(PO4)3F] on Albite [Na(AlSi3O8)]

mineral