Ruby
Corundum var. Ruby · Precious Gemstone
Crystal System
Trigonal; typically occurs as hexagonal prisms, rhombohedral crystals, or rounded pebbles
Mineral Group
Oxides (Hematite group)
Chemical Formula
Al2O3 (with Chromium Cr3+ impurities causing the red color)
Formation Process
Metamorphic (contact or regional metamorphism of aluminous or carbonate rocks) or Igneous (magmatic crystallization in silica-poor rocks)
About This Crystal
Vibrant pinkish-red to deep blood-red gemstone. Exhibits a vitreous (glassy) luster, ranging from transparent to translucent. In the image, the stone shows a round brilliant-style facet cut set in a metal bezel.
Physical Characteristics
Color: Red to purplish-red; Streak: White; Cleavage: None (has parting); Fracture: Conchoidal/Splintery; Specific Gravity: 3.97-4.05; Fluorescence: Strong red under LWUV (especially in Burmese rubies).
Optical Properties
Refractive Index: 1.762-1.770; Birefringence: 0.008; Pleochroism: Strong (purplish-red to orangey-red); Singly refractive but exhibits double refraction due to trigonal structure.
Hardness & Durability
Origin Region
Myanmar (Burma), Mozambique, Thailand, Madagascar, Sri Lanka, and Vietnam
Hardness & Durability
Mohs Hardness: 9.0 (extremely hard, second only to diamond); Toughness: Excellent/High; very durable for daily jewelry wear.
Care & Maintenance
Clean with warm soapy water or ultrasonic cleaners. Generally stable, but avoid harsh chemicals or high heat if stone is fracture-filled (glass-filled).
Rarity & Value
Precious and rare; value is heavily dictated by 'Pigeon Blood' color, clarity, and stone origin. Treatments like heat enhancement are very common.
Special Characteristics
May exhibit asterism (star ruby) or strong fluorescence. The specimen in the photo shows a distinct purplish-pink saturation characteristic of certain alkaline basalt or marble-hosted deposits.
Lore & History
Historically known as the 'King of Precious Stones.' Traditionally associated with the Root Chakra, it symbolizes passion, protection, and prosperity. It has been used by royalty for centuries to represent power and devotion.