Rock Identifier
Ruby in Fuchsite (Corundum (Al2O3) in Fuchsite (K(Al,Cr)3Si3O10(OH)2)) — Mineral
Mineral

Ruby in Fuchsite

Corundum (Al2O3) in Fuchsite (K(Al,Cr)3Si3O10(OH)2)

Hardness: 9 on the Mohs scale. Color: Red (ruby) and green (fuchsite). Luster: Vitreous to sub-adamantine for ruby; pearly to vitreous for fuchsite. Crystal structure: Hexagonal (ruby/corundum). No distinct cleavage for ruby; perfect basal cleavage for fuchsite. Specific gravity: Approximately 3.97-4.05 for ruby.

Hardness
9 on the Mohs scale
Color
Red (ruby) and green (fuchsite)
Luster
Vitreous to sub-adamantine for ruby
Identified More mineral

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Physical properties

Hardness: 9 on the Mohs scale. Color: Red (ruby) and green (fuchsite). Luster: Vitreous to sub-adamantine for ruby; pearly to vitreous for fuchsite. Crystal structure: Hexagonal (ruby/corundum). No distinct cleavage for ruby; perfect basal cleavage for fuchsite. Specific gravity: Approximately 3.97-4.05 for ruby.

Formation & geological history

Metamorphic, typically formed during regional metamorphism where aluminum-rich rocks are subjected to high pressure and temperature. The ruby (corundum) crystals grow within a matrix of fuchsite (a chromium-rich variety of muscovite mica). The presence of chromium is what gives both minerals their color. Geological age varies depending on the specific deposit, but typically associated with ancient metamorphic events.

Uses & applications

Primarily used as an ornamental stone in polished forms such as spheres, cabochons, and carvings. It is popular in lapidary work and for metaphysical or healing practices. Less commonly used as a source for gem-quality ruby, as the ruby inclusions are often opaque and fractured within the fuchsite matrix.

Geological facts

Ruby in Fuchsite is a combination mineral, not a rock type. The ruby crystals are often unevenly distributed within the fuchsite matrix. While individual rubies are highly prized gemstones, ruby in fuchsite is valued more for its ornamental and metaphysical properties. It is often carved into decorative items or tumbled into cabochons.

Field identification & locations

To identify in the field, look for distinct red (ruby) crystals embedded within a sparkly, green (fuchsite) matrix. The green color is a key indicator of fuchsite. Common locations include India (especially Karnataka), Pakistan, Russia, and Afghanistan. Collectors look for good contrast between the red and green, and well-formed ruby crystals. The high hardness of ruby means it will scratch glass and most other common minerals.