Sugilite

Refractive Index : 1.610 – 1.607 (+0.001 – 0.002)

Optical Characteristic : DR U-, AGG

Specific Gravity : 2.74 (+0.05)

Formula : (K,Na)(Na,Fe+3)2(Li2,Fe+3)Si12O30 + Mn.

Crystal System : Hexagonal

Variety/Species : Sugilite

Species/Group : Osumilite group

Birefringence : None to 0.003

Dispersion : N/A

Hardness : 5.5 to 6.5

Toughness : good

Ultrasonic : risky

Steam : risky

UV Long : Inert

UV Short : Inert

Pleochroism : None

Strength : N/A

Pleochroism Colors : None

Heat : stable

Acids : Avoid hydrofluoric acid

Light : stable

Polish Luster : waxy to vitreous

Fracture : granular

Fracture Luster : dull

Clarity Type : N/A

Tones : N/A

Saturations : N/A

Cause of Color : manganese, iron

Enhancements : none

Cleavage : None

Color Range : Red-purple, reddish purple, purple, bluish purple, pink (rare), reddish

Transparency : Semitransparent to opaque

Phenomena : None

Separations : Sugilite from-
Charoite : RI, appearance, spectrum

Amethystine chalcedony : RI, SG, spectrum

Identifying Characteristics and information
Purple color is intense.
May show RI of 1.54 due to quartz impurities.

Spectral Data
Strong band at 4190, weak band at 4110 Broad, diffuse band centered at 5700. Lines at 4370, 4450

Trade Names and Misnomers
Royal Azel
Roysl Lavulite
Sugilite

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