Aquamarine | Gemopedia

The birthstone for March, aquamarine is one of the most popular members of the beryl family, a sibling to emerald, morganite, bixbite, heliodor, and goshenite. The color ranges, depending on the relative concentrations and location of iron within the beryl crystal structure. Aquamarine's tranquil color and crystalline clarity capture the beauty of the sea, which is fitting as its name is formed from the Latin words "aqua," meaning water, and "mare," meaning sea. A favorite among gemstone lapidaries, rough aquamarine is relatively easy to fashion, so lapidaries often create imaginative aquamarine cuts and shapes.
Colors
Greenish Blue To Pale Blue-Green

Aquamarine Classification

Common Name

Aquamarine

Species

Beryl

Variety

Aquamarine

Colors

Greenish Blue To Pale Blue-Green

Alternate Names

Gemstone Groups

Key Separations

refractive index, birefringence, optic character, and Chelsea Colour Filter reaction

Comments

Chatoyancy or asterism are sometimes found in aquamarine. The RI of aquamarine is usually lower than other beryl varieties and runs between 1.569 to 1.575 and the SG tends to be about 2.67.

Aquamarine Optical Properties

Transparency

Transparent - Translucent

Refractive Index

1.577-1.583
Tolerance:(+0.017/-0.017)

Birefringence

0.005-0.009

Optic Character

Uniaxial

Optic Sign

Negative

Polariscope Reaction

Doubly Refractive (DR)

Fluorescence

SWUV: Inert
LWUV: Inert

CCF Reaction

green or blue-green

Pleochroism

Dichroic, weak to moderate blue to slightly darker blue or greenish blue

Dispersion

Strength: weak fire Value: 0.014

Comments

Aquamarine Chemistry & Crystallography

Chemical Name

beryllium aluminum silicate

Chemical Formula

Be3Al2(SiO3)6

Synthesis

Crystal System

Hexagonal

Classification

Silicate

Nature

Natural

Crystallinity

Crystalline

Comments

Aquamarine Characteristic Physical Properties

Hardness

7.5

Streak

White

Specific Gravity

2.67-2.9 Range:0.18/-0.05 Typical:2.72

Toughness

Good

Inclusions

Aquamarine is a type I clarity stone. Stones are typically clean but sometimes contain "fingerprints" and liquid inclusions, 2-phase or 3-phase inclusions, hollow or liquid filled parallel tubes, spiky cavities and tubes parallel to the length of the crystal that look like rain, mica flakes. Crystal inclusions include apatite, almandite and spessartite garnet, quartz and tourmaline. Star aquamarine will have a weak 6 or 4 rayed star and sometimes both.

Luster

Vitreous

Stability

Good

Fracture

Conchoidal

Cleavage

Poor, in one direction

Comments

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