Fuchsite with Ruby

Metamorphic Rock (Metasomatite)

Chromian Muscovite (Fuchsite) with Corundum (Ruby)

Also known as: Ruby in Fuchsite, Ruby Fuchsite, Chromian Muscovite with Corundum

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Description

Fuchsite with Ruby is a striking metamorphic rock composed primarily of green fuchsite (a chromium-rich variety of muscovite) and embedded crystals of red ruby (a chromium-rich variety of corundum). The vibrant green matrix provides a stark and beautiful contrast to the deep red to pinkish-red ruby crystals, which can range from opaque to translucent. The ruby crystals often appear as hexagonal prisms or irregular masses within the micaceous matrix. The rock can also contain other accessory minerals such as kyanite, margarite, rutile, and various amphiboles, depending on the specific geological conditions of its formation.

How to Identify

Color: Vibrant green (fuchsite) with contrasting red to pinkish-red (ruby) inclusions. The green can vary in intensity, and the ruby can be opaque to translucent.
Luster: Fuchsite: Pearly to vitreous. Ruby: Adamantine to vitreous.
Texture: Schistose or foliated due to the micaceous nature of fuchsite, with harder, granular ruby crystals embedded within. Can feel somewhat greasy or soapy due to the mica.
Crystal Form: Fuchsite: Platy, flaky, or massive aggregates. Ruby: Hexagonal prisms, tabular, or anhedral (irregular) grains.
Cleavage: Fuchsite: Perfect basal cleavage in one direction, producing thin, flexible sheets. Ruby: No cleavage, but exhibits parting along basal and rhombohedral planes.
Geological Environment: Metamorphic terrains, particularly those derived from chromium-rich mafic or ultramafic protoliths, often associated with regional or contact metamorphism and metasomatic alteration.

Key Facts

Hardness: Fuchsite: 2.5-3 (Mohs). Ruby: 9 (Mohs). The overall rock hardness is variable.
Specific Gravity: Fuchsite: 2.77-2.88. Ruby: 3.97-4.05. The rock's specific gravity will be an average of its components.
Crystal System: Fuchsite: Monoclinic. Ruby: Hexagonal (Trigonal).
Color: Green (fuchsite) and Red (ruby).
Luster: Pearly (fuchsite) to Vitreous/Adamantine (ruby).
Transparency: Fuchsite: Translucent to opaque. Ruby: Opaque to translucent, rarely transparent.
Fracture: Fuchsite: Uneven to splintery. Ruby: Conchoidal to uneven.
Cleavage: Fuchsite: Perfect basal cleavage {001}. Ruby: No cleavage, but parting on {0001} and {1011}.
Composition: Fuchsite: K(Al,Cr)2(AlSi3O10)(OH)2 (Chromian Muscovite). Ruby: Al2O3 (Chromian Corundum).

Quick Check

Color: Green with red inclusions
Luster: Pearly (fuchsite) to Vitreous/Adamantine (ruby)
Streak: White (fuchsite), White (ruby)

Physical Characteristics

Crystal Habit: Fuchsite: Micaceous, platy, foliated. Ruby: Prismatic, tabular, granular, massive.
Cleavage Type: Fuchsite: Perfect basal. Ruby: None (parting present).
Fracture Type: Fuchsite: Uneven to splintery. Ruby: Conchoidal to uneven.
Tenacity: Fuchsite: Flexible, elastic. Ruby: Brittle.
Luster Type: Fuchsite: Pearly. Ruby: Vitreous to adamantine.

Formation

Fuchsite with Ruby forms in metamorphic environments, specifically within chromium-rich mafic or ultramafic rocks (such as serpentinites or amphibolites) that have undergone regional or contact metamorphism. The presence of chromium is essential for the green color of fuchsite and the red color of ruby. Ruby (corundum) typically forms in aluminum-rich, silica-poor environments, often associated with desilication processes or metasomatism where fluids introduce or remove specific elements. The fuchsite matrix is a chromium-rich variety of muscovite, indicating the presence of chromium during its formation. This rock is often found in zones of intense shearing and alteration.

Usage

Primarily used as an ornamental stone, for carvings, cabochons, spheres, and other lapidary applications. It is also popular in metaphysical and crystal healing communities. Due to the hardness contrast between ruby and fuchsite, it is less commonly used in fine jewelry where durability is paramount, though smaller polished pieces are sometimes incorporated.

Age Distribution

Precambrian to Paleozoic, depending on the specific geological setting of metamorphism.

Where to Find

India

Significant deposits, particularly in the Karnataka and Andhra Pradesh states, where it is mined for ornamental purposes.

Brazil

Known localities producing good quality specimens.

Russia

Ural Mountains region, known for various chromium-rich metamorphic rocks.

Pakistan

Some occurrences reported.

Madagascar

Known for a variety of gem and ornamental stones, including some ruby-bearing metamorphic rocks.

Finding Tips

Geological Context

Look for areas with known occurrences of chromium-rich metamorphic rocks, such as serpentinites, amphibolites, or talc schists, especially in ancient shield areas or orogenic belts.

Color and Luster

The distinctive green of fuchsite and red of ruby make it relatively easy to spot. The pearly luster of fuchsite and the vitreous to adamantine luster of ruby are also key identifiers.

Associated Minerals

Often found with other metamorphic minerals like kyanite, margarite, and various amphiboles, which can indicate a favorable geological environment.

Hardness Test

While not definitive for the rock as a whole, testing the hardness of individual components can help. Ruby (9 on Mohs) will scratch fuchsite (2.5-3 on Mohs) and most other common minerals.

Similar Rocks

Anyolite

Corundum (Ruby) in Zoisite

Also known as: Ruby in Zoisite

Ruby in Kyanite

Corundum (Ruby) in Kyanite

Also known as: Ruby Kyanite

Verdite

Fuchsite-rich rock

Also known as: African Jade

Scientific Classification

Mineral Class: Fuchsite: Phyllosilicate (Mica Group). Ruby: Oxide (Corundum Group).
Group: Fuchsite: Muscovite subgroup. Ruby: Corundum group.
Crystal System: Fuchsite: Monoclinic. Ruby: Trigonal (Hexagonal).
Chemical Formula: Fuchsite: K(Al,Cr)2(AlSi3O10)(OH)2. Ruby: Al2O3 (with trace Cr).
Composition: Fuchsite is a potassium aluminum silicate hydroxide with significant chromium substitution for aluminum. Ruby is aluminum oxide with trace chromium impurities responsible for its red color.

Explore Fuchsite with Ruby

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