Elbite Tourmaline | Gemopedia

Copper-containing elbaite tourmalines from the State of Paraiba, Brazil are uniquely colored gems. This variety of tourmaline includes vivid greenish blue, deep blue, and bright, saturated greens. Tourmaline is derived from the Sinhalese word turamali meaning mixed or stone of mixed colors, likely because of the variety of colors it's found in.

Elbite Tourmaline Classification

Common Name

Elbite Tourmaline

Species

Tourmaline

Variety

Elbite Tourmaline

Colors

green, blue, red, orange, yellow, colorless

Alternate Names

Gemstone Groups

Key Separations

appearance, refractive index and high birefringence; then optic figure, pleochroism and specific gravity

Comments

Dark material might have birefringence as high as 0.040Paraba Tourmaline is a Cuprian Elbaite.Rubellite is the red to pink variety.

Elbite Tourmaline Optical Properties

Transparency

Transparent To Translucent

Refractive Index

1.614-1.666

Birefringence

0.014-0.032

Optic Character

uniaxial

Optic Sign

negative

Polariscope Reaction

doubly refractive (DR)

Fluorescence

SWUV: Generally Inert
LWUV: Generally Inert

CCF Reaction

Pleochroism

Value: usually medium to strong, sometimes two different shades of body color, sometimes two quite different colors

Dispersion

Strength: moderate fire Value: 0.017

Elbite Tourmaline Chemistry & Crystallography

Chemical Name

complex boro-silicate of Al, Mg and Fe

Chemical Formula

Na(Li1.5Al1.5)Al6(Si6O18)(BO3)3(OH)3(OH)

Synthesis

Crystal System

Trigonal

Classification

Silicate

Nature

Natural

Crystallinity

Crystalline

Elbite Tourmaline Characteristic Physical Properties

Hardness

7 to 7.5

Streak

white

Specific Gravity

2.9-3.1

Toughness

Good

Inclusions

Green elbite tourmaline stones are type I clarity stones. Blue, purple, orange, yellow and bi-color or parti-colored elbite tourmalines are type II clarity stones. Stones might contain liquid and gas inclusions that are long and thin, reflective gas-filled fractures and color zoning.

Luster

Vitreous

Stability

Very Good

Fracture

Conchoidal To Uneven

Cleavage

Difficult, Indistinct

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