Ruby
Corundum var. Ruby · Precious Gemstone
Crystal System
Trigonal, typically forming barrel-shaped, prismatic, or tabular hexagonal crystals, often with flat terminations.
Mineral Group
Oxides
Chemical Formula
Al2O3 (Chromium trace elements substituting for aluminum)
Formation Process
Metamorphic and igneous processes, typically in silica-deficient environments like marbles subject to regional or contact metamorphism.
About This Crystal
A small, vivid pinkish-red to red crystal fragment with a vitreous to sub-adamantine luster and translucent to transparent clarity.
Physical Characteristics
Color is vivid red due to chromium; white streak; no true cleavage but exhibits parting; conchoidal to uneven fracture; specific gravity around 4.00; brittle tenacity.
Optical Properties
Singly refractive (uniaxial negative); strong dichroism showing purplish-red and orangey-red from different angles.
Hardness & Durability
Origin Region
Notable sources include Myanmar (Burma), Mozambique, Thailand, Madagascar, and Sri Lanka. Forms in marbles and metamorphic terrains.
Hardness & Durability
Mohs hardness of 9, making it extremely durable and second only to diamond, ideal for everyday jewelry wear.
Care & Maintenance
Safe for ultrasonic cleaners and warm soapy water unless severely fractured; store separately to prevent scratching softer stones.
Rarity & Value
Rare to very rare depending on size, clarity, and lack of treatments; highly valued in the gemstone market; heat treatment is very common.
Special Characteristics
May exhibit strong red fluorescence under long-wave ultraviolet light due to chromium content.
Lore & History
Historically regarded as the 'King of Gems', symbolizing passion, protection, and prosperity. Associated with the root chakra in modern crystal healing traditions.