Garnet in Matrix (Eclogite)

Physical Properties

Hardness: 6.5-7.5 (garnet), 5-6 (matrix); Color: Deep burgundy/red garnets set in a dark green to black pyroxene matrix; Luster: Vitreous to resinous; Crystal structure: Isometric (garnets); Specific gravity: 3.5-4.3.

Formation & Geological History

Formed under extreme high-pressure and high-temperature conditions in the Earth's mantle or deep crust during subduction or mountain-building events. These rocks are typically millions of years old.

Uses & Applications

Used primarily for ornamental purposes, decorative carvings (like the tower shown), lapidary art, and occasionally as an abrasive due to garnet hardness.

Geological Facts

Eclogite is often called the 'Christmas Rock' because of its striking combination of red garnets and green omphacite. It provides geologists with critical information about the deep processes of plate tectonics.

Field Identification & Locations

Identify by the presence of rounded, dark red garnet crystals embedded in a dense, dark host rock. Commonly found in metamorphic terranes like those in Norway, the Alps, or the Appalachian mountains.

Identified on: 4/29/2026

Mode: Standard