Description
Black crystal opal has a body tone between N1 and N4 while most crystal opals have a body tone of N5 to N7.
Variety: Natural Black Opal Type 1
Body Tone: Black N4 (7)
Brightness: Slightly Bright
Transparency: Translucent
Colour: Orange-Multi
Hue: Normal Tones
Outline: Oval Shape
Profle: Medium Cabochon
Origin: Lighting Ridge
Pattern: Named Pattern
Display: Weak or Blank 1 Angle
Distribution: 40 – 49%
Inclusions: 5% of Face
MOHS Scale: 4.5-6.5
Polish: 2.15+0.08-0.09
R.F.I.: 1.450+0.020
Spec Gravity: 1.98 – 2.25
Carat Weight: 1.16 Carats
Formula: Si02nH20
Fracture: Conchoidal – Uneven
Lustre: Vitreous – Resinous
Flourescence: May phosphoresce in long /short wave
Absorption: Spectra 660nm, 470nm
Category: Mineraloid (Amorphorous)
Crystal Habit: Irregular ‘nodular’ Veins
Composition: Hydroussilicondioxide.3-21%/weight
Crystal Form: Amorphous, pseudomorph, botryoidal