Opal Fire — Precious Opal Play-of-Colour at 3:1 Macro
38.56 د.ك
Australian precious opal photographed at 3:1 macro — the silica sphere diffraction grating producing the characteristic play-of-colour: vivid reds, greens, and blues in a shifting iridescent pattern across a 10mm section of the gemstone.
Description
Precious opal’s play-of-colour is produced by a three-dimensional diffraction grating — the regular packing of silica spheres of 150-300nm diameter creates a photonic crystal that diffracts visible light into its spectral components. The colour observed depends on the sphere diameter (which determines the wavelength reflected), and the mosaic of differently oriented sphere-packing domains in the opal produces the characteristic shifting colour pattern as the viewing angle changes. At 3:1 macro reproduction of a high-quality Lightning Ridge black opal, the play-of-colour pattern is fully legible — the colour domains in their characteristic angular forms, the colour sequence from red through orange, yellow, green, and blue visible as the viewing angle changes within the single frame due to the slight curvature of the opal’s surface. The black potch background that makes black opal’s colour the most vivid is visible in the un-coloured regions between the play-of-colour domains.
