Eclogite

Physical Properties

Hardness: 6.5-7.5. Color: Red/brown (garnet) and green/dark (pyroxene). Luster: Vitreous to dull. Structure: Granular, non-foliated. High density (~3.4–3.5 g/cm³).

Formation & Geological History

Forms under ultra-high pressures and temperatures (mantle depths >50km) during subduction of oceanic crust into the upper mantle. Often metamorphic facies.

Uses & Applications

Primarily of interest to researchers for studying plate tectonics; occasionally used as a decorative stone or abrasive garnet source.

Geological Facts

Eclogite is often called the 'Christmas Tree Rock' because of its classic red garnet and green pyroxene colors. It is rarer than other metamorphic rocks at the surface.

Field Identification & Locations

Check for high density and the presence of red garnets embedded in a dark/greenish matrix. Commonly found in xenoliths in kimberlites or as tectonic lenses in mountain belts like the Alps or Norway.

Identified on: 5/1/2026

Mode: Standard