Eclogite

Physical Properties

Hardness: 6.5-7.5 (Mohs scale); Color: Typically distinctive red/pink (garnet) and green (omphacite); Luster: Vitreous to dull; Crystal structure: Granular; Specific gravity: 3.2-3.6.

Formation & Geological History

Formed under extreme pressure conditions (high-pressure metamorphism) often in subduction zones at depths of 50 km or more in the Earth's mantle or lower crust.

Uses & Applications

Primarily of interest to research geologists for studying tectonic plate movement; occasionally used as a decorative stone or for heavy industry abrasives.

Geological Facts

Eclogites are sometimes referred to as 'Christmas trees' due to their vibrant red and green coloration. They represent the highest grade of metamorphism (eclogite facies).

Field Identification & Locations

Identify in the field by its high density and the presence of pinkish-red garnets embedded in a dense matrix. Common in mountain belts like the Alps or the Appalachian Mountains.

Identified on: 5/1/2026

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