Amethyst

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: Amethyst Geode

: Amethyst Pendent

: Amethyst Bead Necklace

: Amethyst Crystal

: Rough Natural Amethyst

: Transparent natural amethyst

Natural Amethyst Gemstone – Purple Quartz Crystal

Refractive Index : 1.553 – 1.544

Optical Characteristic : DR Uniaxial positive, AGG

Specific Gravity : 2.66 (+0.03 – 0.02)

Formula : SiO2

Crystal System : Trigonal

Variety/Species : Amethyst

Species/Group : Quartz

Birefringence : 0.009

Dispersion : 0.013

Hardness : 7

Toughness : Good

Ultrasonic : Usually Safe

Steam : Risky

UV Long : Inert to Weak

UV Short : Inert to Weak blue

Pleochroism : 2 Colors

Strength : Weak to Moderate

Pleochroism Colors : Weak to moderate: Purple /reddish purple.

Heat : Avoid heating

Acids : Avoid hydrofluoric acid

Light : Some may fade

Polish Luster : Vitreous

Fracture : Conchoidal

Fracture Luster : Vitreous

Clarity Type : II

Tones : 2-8

Saturations : 1-5

Cause of Color : Color centers involving iron impurities and irradiation

Enhancements : Heating

Cleavage : None

Color Range : Daylight: Purple, violet, bluish violet, violet, bluish purple Incandescent light red, purple, reddish purple, purple-red, red-purple, purplish red, Purplish, reddish, violetish

Transparency : Transparent to Translucent

Phenomena : None

Separations : Amethyst from-
Iolite : color, optic character sign, pleochroism, SG, cleavageSynthetic amethyst : magnification, Brazil law twinning pattern seen under polarized lightScapolite : optic sign, cleavage,(RI, birefringence, SG, optic character, all possibly)

Identifying Characteristics and information
Color zoning, twinning, two-phase inclusions, negative crystals, rutile needles three-phase inclusions, may show bulls eye or Airys spiral optic fiqure.Rose of france is a pale, lilac shade of amethyst.

Spectral Data
Not Diagnostic.

Trade Names and Misnomers
Amethyst
Rose of France
Siberian Amethyst
Uralian Amethyst

Tags: Amethyst, Natural amethyst, Rose of France, Siberian Amethyst, synthetic amethyst, Uralian Amethyst