Adularescence in a moonstone cabochon, Minas Gerais, Brazil. The specimen's diameter is 23 mm (0.91 in).
Descriptionedit
The effect of adularescence, also commonly referred to as schiller or shiller, is best described as a milky, bluish luster or glow originating from below the surface of the gemstone. The schiller, appearing to move as the stone is turned (or as the light source is moved), gives the impression of lunar light floating on water (accounting for moonstone's name).[1] Though white schiller is the most common, in rarer specimens, orange or blue lusters are produced.[2]
This effect is most typically produced by adularia, a K-feldspar or orthoclase (KAlSi3O8), from which the name is derived.[3][4][5] Adularescence appears in numerous other gemstones, notably common opal, rose quartz and agate. However, due to inclusions in these other stones, the effect is displayed differently. The schiller is scattered by inclusions and appears hazy; non-hazy specimens are specially referred to as "milky". Thus, adularescence occurring in non-adularia gemstones is termed differently – the "girasol effect" and opalescence (for opals only) are two such terms. When the schiller forms an indistinct band, it is said to display a chatoyant effect. Only clearly defined bands are referred to as "cat's eyes".[5]
As an optical phenomenon, adularescence exists only in the presence of light; it is a product of the interaction between light and the internal microstructures of the mineral and not a property of the mineral itself. The effect is produced by alternating layers of two types at a scale near the wavelength of light (approximately 0.5 micron) – this leads to light scattering and interference.[6]
^ abShipley, Robert M. (2007), Dictionary of Gems and Gemology, Read Books, p. 93.
^Nassau, Kurt (1978). "The origins of color in minerals," American Mineralogist, vol. 63, pp. 219-229.
April 10, 2024
adularescence, əns, optical, phenomenon, that, produced, gemstones, like, moonstone, optical, effect, similar, labradorescence, aventurescence, moonstone, cabochon, minas, gerais, brazil, specimen, diameter, description, editthe, effect, adularescence, also, c. Adularescence ˌ ae dʒ e l e ˈ r ɛ s en s AJ e le RES ens is an optical phenomenon that is produced in gemstones like moonstone The optical effect is similar to labradorescence and aventurescence Adularescence in a moonstone cabochon Minas Gerais Brazil The specimen s diameter is 23 mm 0 91 in Description editThe effect of adularescence also commonly referred to as schiller or shiller is best described as a milky bluish luster or glow originating from below the surface of the gemstone The schiller appearing to move as the stone is turned or as the light source is moved gives the impression of lunar light floating on water accounting for moonstone s name 1 Though white schiller is the most common in rarer specimens orange or blue lusters are produced 2 This effect is most typically produced by adularia a K feldspar or orthoclase KAlSi3O8 from which the name is derived 3 4 5 Adularescence appears in numerous other gemstones notably common opal rose quartz and agate However due to inclusions in these other stones the effect is displayed differently The schiller is scattered by inclusions and appears hazy non hazy specimens are specially referred to as milky Thus adularescence occurring in non adularia gemstones is termed differently the girasol effect and opalescence for opals only are two such terms When the schiller forms an indistinct band it is said to display a chatoyant effect Only clearly defined bands are referred to as cat s eyes 5 As an optical phenomenon adularescence exists only in the presence of light it is a product of the interaction between light and the internal microstructures of the mineral and not a property of the mineral itself The effect is produced by alternating layers of two types at a scale near the wavelength of light approximately 0 5 micron this leads to light scattering and interference 6 See also editAventurescence Labradorescence Optical phenomenon Rainbow lattice sunstoneReferences edit Long Bill 2004 Varieties of Light II Pleochroism Nacreous Adularescence A d venturescence Archived 2008 12 29 at the Wayback Machine Semi Precious Stones Guide List of Gemstone Phenomena King R J 1990 Minerals explained 12 Alkali feldspar Part 2 Geology Today 6 pp 27 29 Adularescence reference com a b Shipley Robert M 2007 Dictionary of Gems and Gemology Read Books p 93 Nassau Kurt 1978 The origins of color in minerals American Mineralogist vol 63 pp 219 229 Retrieved from https en wikipedia org w index php title Adularescence amp oldid 1170579757, wikipedia, wiki, book, books, library,
