Description
Black opal is the rarest variation of the stone.
Variety: Natural Black Opal Type 1
Body Tone: Black N2 (4)
Brightness: Slightly Dull
Transparency: Opaque
Colour: Blue-Orange
Hue: Pale Tones
Outline: Oval Shape
Profle: Medium Cabochon
Origin: Lighting Ridge
Pattern: Broad Flash Pattern
Display: Weak or Blank 2 Angles
Distribution: 30 – 39%
Inclusions: 20% 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: .95 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