Limonite-in-Topaz


BurmaIn the Summer of 1987, The Gemological Institute of America (GIA) published an article in their journal that discussed the difference between rutilated topaz and limonated topaz. The needle-like inclusions in so-called "rutilated topaz" are actually limonite staining that fills hollow tubes in the topaz. In fact rutile is not known to crystallize at all in topaz in a ribbon-like form that would produce effects similar to those in rutile quartz.Limonite is quite a different mineral from rutile. Rutile is titanium dioxide and has an exceptionally high refractive index, much higher than diamond. Limonite is actually not itself a true mineral, rather it is a combination of iron oxide minerals such as goethite and lepidocrocite. Typically yellow-brown in color, limonite is used as the basis for the natural earth pigment ochre.Thus the name "rutilated topaz" is a misnomer, clearly derived from the better-known "rutilated quartz". One can only surmise that the name persists because its true name of "Limonite-stained Topaz" would have greater difficulty in gaining public acceptance. The present stone is a high-domed cabochon displaying excellent polish to the nearly optically clear topaz with limonite inclusions. Suitable either for mounting as a pendant or to be retained a cabinet specimen/collector's stone. Weighing approximately 114.5 carats and measuring 28.65 x 20.33 x 18.87mm