Emerald Vivid Green Great Color And Luster From Swat Valley 0.85 Ctw

Description

Natural Emerald vivid green Color ( Beryl ) from Pakistan(Swat valley) good clarity and lustrous
Weight , 0.85 ctw
Dimensions, 7 x 5 x 4 mm
More About Emerald Stone
Emerald is a gemstone and a variety of the mineral beryl (Be3Al2(SiO3)6) colored green by trace amounts of chromium and sometimes vanadium.[2] Beryl has a hardness of 7.5–8 on the Mohs scale.[2] Most emeralds are highly included,[3] so their toughness (resistance to breakage) is classified as generally poor. Emerald is a cyclosilicate.
Category -Beryl variety
Formula -Be3Al2(SiO3)6
Crystal system- Hexagonal (6/m 2/m 2/m) Space group: P6/mсc
Space group - (6/m 2/m 2/m) – dihexagonal dipyramidal
Unit cell - a = 9.21 Å, c = 9.19 Å; Z = 2 - Identification
Formula mass - 537.50
Color - Green shades to colorless
Crystal habit - Massive to well Crystalline
Cleavage - Imperfect on the [0001]
Fracture - Conchoidal
Mohs scale hardness - 7.5–8
Luster - Vitreous
Streak - White
Diaphaneity - Transparent to opaque
Specific gravity - Average 2.76
Optical properties - Uniaxial (−)
Refractive index - nω = 1.564–1.595, nε = 1.568–1.602
Birefringence - δ = 0.0040–0.0070
Ultraviolet fluorescence
None (some fracture-filling materials used to improve emerald's clarity do fluoresce, but the stone itself does not)