Ruby in Zoisite
Zoisite var. Anyolite (containing Ruby inclusions) · Decorative Stone and Mineral Specimen
Crystal System
Orthorhombic (Zoisite) and Trigonal (Ruby)
Mineral Group
Silicates (Sorosilicate)
Chemical Formula
Ca2Al3(SiO4)(Si2O7)O(OH) with inclusions of Al2O3:Cr
Formation Process
Metamorphic, specifically formed through regional metamorphism where aluminum-rich corundum comes into contact with calcium-rich rocks under high temperature and pressure.
About This Crystal
The specimen exhibits a striking color contrast between vibrant pink-to-red corundum (ruby) crystals embedded within a predominantly opaque, light-to-dark green zoisite matrix, often intertwined with black hornblende. The luster is vitreous to pearly on cleavage planes, and the texture is dense and massive.
Physical Characteristics
Color: Green matrix with pink/red spots and black inclusions. Streak: White. Cleavage: Perfect in one direction for zoisite. Fracture: Uneven to conchoidal. Specific Gravity: 3.35 to 3.36. Tenacity: Brittle. Fluorescence: Ruby portions fluoresce a strong red under UV light.
Optical Properties
Refractive Index: 1.691-1.700 (Zoisite). Birefringence: Weak to moderate. Pleochroism: Noticeable in the ruby component from purplish-red to brownish-red. Doubly refractive.
Hardness & Durability
Origin Region
Tanzania (Longido region), Kenya, and India; forms in metamorphic environments
Hardness & Durability
Mohs hardness varies across the specimen due to mixed minerals: Zoisite is 6 to 7, while Ruby is 9. Overall durability is moderate; toughness can be compromised by fractures between the differing mineral boundaries.
Care & Maintenance
Clean with warm soapy water and a soft brush. Avoid harsh chemical cleaners, ultrasonic cleaners, and sudden extreme temperature changes due to the differing thermal expansion rates of the constituent minerals.
Rarity & Value
Uncommon to Rare depending on the size, color saturation, and distribution of the ruby crystals within the green zoisite matrix. Values range from affordable tumbled stones to higher-priced carved decorative collector specimens.
Special Characteristics
Strong red UV fluorescence from the ruby inclusions and a natural polychromatic contrast combining two distinct mineral species (red corundum and green zoisite) into a single decorative stone.
Lore & History
Discovered in 1954 in Tanzania, Anyolite is often referred to as Tanganyika art stone. In modern crystal healing lore, it is believed to combine the energies of growth and vitality (green zoisite) with passion and courage (ruby), associated primarily with the heart and root chakras.