TOPAZ

With its wide range of colours and lustre, a transparent Topaz is a highly desirable gemstone. Colourless Topaz also has its charms, with a variety of typical inclusions which can elevate an unexceptional gem into a fascinating specimen. Limonite-filled hollow tubes appear as golden or red needles, iridescent acicular inclusions reflect light into spectral colours and a host of unusual interior features add to this gemstones allure.
Topaz is an Aluminium/Fluorine Silicate, chemical composition Al₂SiO₄(F,OH)₂ and occurs in many localities, most notably Brazil, Myanmar and Sri Lanka.  Blue Topaz is not common in nature and most faceted examples are heat treated, while the famed Imperial Topaz, with colours ranging from pale yellow to orange to pink is only mined in Ouro Preto, Brazil.