Viridine

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Refractive Index : 1.643 – 1.634 (+ 0.005 – 0.005)

Optical Characteristic : DR, Biaxial negative, AGG

Specific Gravity : 3.17 + 0.04 – 0.04

Formula : AI2SiO5=AI[6]A[5]OSiO4

Crystal System : Orthorhombic

Variety/Species : Andalusite

Species/Group : Andalusite

Birefringence : 0.007 – 0.003

Dispersion : 0.016

Hardness : 7 to 7.5

Toughness : Fair to good

Ultrasonic : Uaually safe

Steam : Risky

UV Long : Inert

UV Short : Inert to moderate

Pleochroism : 2 or 3 colors

Strength : Strong

Pleochroism Colors : Strong(usually):Yellow/green/red

Heat : Stable unless has liquid inclusions

Acids : No reaction

Light : Stable

Polish Luster : Vitreous

Fracture : Uneven to conchoidal

Fracture Luster : Vitreous

Clarity Type : II

Tones : 3-6

Saturations : 2-4

Cause of Color : Green-maganese

Enhancements : Heating, dyeing

Cleavage : Distinct in 1 direction

Color Range : Green, greenish

Transparency : Transparent to opaque

Phenomena : None

Separations : Viridine from-Tourmaline : Birefringence, optic character, pleochroism, SG, spectrum(possibly)

Chrysoberyl : RI, SG, pleochroism, spectrum

Apatite : optic character, pleochroism, birefringence, color, spectrum

Identifying Characteristics and information
Strong pleochroism, usually yellow/green/red, needle-like inclusions(rutile crystals). May fluoresce green to yellowish green(SW). Andalusite is trimorphous with kyanite and sillimanite. May show only 2 colors of pleochroism

Spectral Data
Shadow at 5535, lines at 5505,5475; faint at 5180,4950,4550

Trade Names and Misnomers
Viridine

Tags: Andalusite, Orthorhombic, Viridine