Lightning Ridge in New South Wales, Australia, is the world’s sole commercial source of black opal — the most valuable and coveted of all opal varieties, defined by a dark body tone (N1 to N4 on the OAA body tone scale) against which the play-of-colour is displayed with extraordinary vividness and contrast. The dark body tone of a black opal acts as a perfect background for the spectral colour display, producing a depth and intensity of colour quite impossible to achieve against the pale base of white or crystal opal — the vivid colours appear to glow from within the dark stone with an electric, luminous quality of remarkable optical power. This Lightning Ridge black opal cabochon displays an outstanding rolling flash play-of-colour in vivid blue and bright emerald-green — large, sweeping colour areas that roll and shift across the dark face as the viewing angle changes, the blue transitioning into green in broad, flowing patches of considerable spectral richness. The body tone is a deep dark grey-black (approximately N2-N3), providing an excellent dark foundation for the vivid colour display. The rolling flash pattern — where broad areas of colour sweep across the face like a wave — is among the most sought-after of all opal colour patterns. Natural black opal. Origin: Lightning Ridge, New South Wales, Australia | Body tone: N2–N3 | Play-of-colour: blue-green rolling flash | Cut: Cabochon | Brightness: 4/5
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