Natural Black Opal Type 1 Blue/Green Oval from Lightning Ridge – 5.18 Carats

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Natural Black Opal Type 1, 5.18 carats, from Lightning Ridge. Features bright blue/green hues, translucent clarity, black N1 body tone, and an oval low cabochon shape. Valued at $1813.

Description

Discover the exceptional beauty of this Natural Black Opal Type 1, a remarkable gemstone from Lightning Ridge, showcasing these exquisite features:

  • Variety: Natural Black Opal Type 1
  • Body Tone: Black N1 (1)
  • Brightness: Bright
  • Transparency: Translucent
  • Colour: Blue/Green with normal tones
  • Shape: Oval Outline
  • Profile: Low Cabochon
  • Pattern: Mixed Pattern
  • Display: Weak or blank from one angle
  • Colour Distribution: Over 80% coverage
  • Inclusions: Loupe visible only

Physical Properties:

  • MOHS Scale: 4.5 – 6.5
  • Polish: 2.15 ± 0.08-0.09
  • Refractive Index (R.I.): 4.450 ± 0.020
  • Specific Gravity: 1.98 – 2.25
  • Carat Weight: 5.18 Carats
  • Formula: SiO₂nH₂O
  • Fracture: Conchoidal – Uneven
  • Lustre: Vitreous to Resinous
  • Fluorescence: May phosphoresce under long/short wave UV
  • Absorption Spectra: 660nm, 470nm

Additional Information:

  • Category: Mineraloid (Amorphous)
  • Crystal Habit: Irregular ‘nodular’ veins
  • Composition: Hydrous silicon dioxide (3-21% water content)
  • Crystal Form: Amorphous, pseudomorph, botryoidal

Valuation:

  • Price Per Carat: $350
  • Total Value: $1813

This opal, with its bright blue-green hues, black N1 body tone, and translucent clarity, stands out as a rare and elegant gemstone, perfect for collectors and jewelry connoisseurs.

Note: This assessment is for insurance purposes and is intended for private and confidential use only.