Aquamarine
Aquamarine | |
---|---|
Chemical composition | Be3Al2(SiO3)6 Beryllium aluminum silicate |
Crystal system | Hexagonal |
Habit | Prismatic |
Cleavage | Imperfect, basal, almost never seen |
Hardness | 7.5 to 8 |
Optic nature | Uniaxial - |
Refractive index | 1.577-1.583 (+0.017, - 0.017) |
Birefringence | 0.005-0.009 |
Dispersion | Low, 0.014 |
Specific gravity | 2.72 (+0.18,-0.5) |
Lustre | Vitreous |
Pleochroism | Weak to moderate |
Aquamarine is a pastel greenish-blue variety of the mineral beryl and owes it's color to the presence of iron impurities. Its name is derived from the Latin words for water (aqua) and sea (marine). Crystals form in large hexagonal prisms. In ancient times, it was believed that sailors wearing aquamarine pendants would be protected from the perils of the sea. The stone symbolized happiness and eternal youth. It was viewed in Christian symbolism to bring moderation and control of passions to its owner.
Beauty is in the eye of the beholder
In the past, the natural greenish-blue color of aquamarine was considered the most desirable. Today, the usual color that we see of Aquamarine is a pale pastel blue. The most sought after color is a deep blue, as typified by the "Santa Maria", "Santa Maria d'Afrique" and "Marta Rocha" aquamarine finds.
Treatments
Routinely heat treated, which removes the green cast, leaving only the blue.
Typical inclusions
Rain inclusions