Aquamarine
Beryl var. Aquamarine · Precious Gemstone
Crystal System
Hexagonal; typically hexagonal prismatic habit with flat pinacoid terminations
Mineral Group
Silicates (specifically Cyclosilicates)
Chemical Formula
Be3Al2Si6O18 with Fe2+ and Fe3+ (iron) trace elements responsible for blue/green color
Formation Process
Igneous/Hydrothermal: Formed late-stage in granite pegmatites and metamorphic rocks through hydrothermal processes involving beryllium-rich fluids.
About This Crystal
Large emerald-cut center stones exhibiting a light cyan-blue to greenish-blue hue. Typical for aquamarine, these stones show a vitreous luster and are transparent with characteristic liquid-filled inclusions (rain), appearing slightly hazy or included.
Physical Characteristics
Color: Pale blue to deep sea-green; Streak: White; Cleavage: One direction (imperfect/poor); Fracture: Conchoidal to uneven; Specific Gravity: 2.66–2.80; Tenacity: Brittle; Fluorescence: Generally inert.
Optical Properties
Refractive Index: 1.577–1.583; Birefringence: 0.005–0.009 (uniaxial negative); Pleochroism: Weak to moderate, showing colorless to light blue/blue-green.
Hardness & Durability
Origin Region
Notable sources include Brazil (Minas Gerais), Madagascar, Pakistan, Nigeria, and Mozambique; typically occurs in granite pegmatites.
Hardness & Durability
Mohs Hardness: 7.5 to 8.0; Toughness: Fair to good; Stability: Stable to light, but sensitive to high heat (can change color) and hydrofluoric acid.
Care & Maintenance
Wash with warm soapy water and a soft brush; avoid ultrasonic or steam cleaners if inclusions are present. Store away from sunlight and separate from harder stones like sapphire or diamond.
Rarity & Value
Common to Uncommon; Value is driven by color saturation (deeper blue is more valuable), clarity, and size. Most commercial aquamarine is heat-treated to remove yellow/green tones.
Special Characteristics
Can exhibit chatoyancy (cat's eye) or asterism occasionally; often contains 'two-phase' inclusions (gas and liquid) or needle-like inclusions of ilmenite or hematite.
Lore & History
Historically used by sailors as a talisman for protection at sea; symbolically known as 'The Stone of Eternal Youth' and 'Stone of Courage.' Traditional associations include the Throat Chakra and calming the mind.