Beryl#Golden beryl and heliodor
Golden beryl is a pale yellow to greenish yellow ( Heliodor ) variety of the mineral beryl ( Be3Al2 [ Si6O18 ] ). Its chemical and physical properties are consistent with those of the other Beryllvarietäten. In contrast to the emerald he has, however, rarely inclusions.
The yellow color of beryl occurs when the in the chemical formula okatedrisch textured aluminum is replaced by Fe3 . However, it can be in nature produced or enhanced by emission of alpha, beta and gamma radiation from adjacent, radioactive minerals such as zircon, columbite, uraninite or other. Because of the radiation ionizes Fe2 to Fe3 , where the formerly blue color gradually turns over greenish blue to yellow.
Sites and discovery
Beryl is usually found in the same kind of deposit the aquamarine. The most important localities are Sri Lanka and South Africa.
Beryl was found probably the first time in 1912 in the Rössing mine in what was then German South-West Africa (now Namibia). The magazine The Week writes in 1913 by the " new German Gemstone Heliodor ":
" German South West Africa, our often -maligned unjustly colony to which we owe quite significant diamond discoveries, has given the world a new gemstone that, Heliodorus ', the discovery of which we actually came about by accident. "
They took the stone in the gem charm loop Trale to Idar -Oberstein, where examined him the jeweler and gemologist Wilhelm Lucas von Cranach and gave him the name Heliodorus. According Cranach it was indeed a previously unknown stone, which should not be confused despite his gold coloring to the golden beryl. The color of the Goldberylls he falsely led back to chromium oxide, iron oxide that of Heliodorus. Kaiser Wilhelm II liked the stone so well that he compared him to " the color of beautiful old Mosel wine ."
Use as a gemstone
Golden Beryl Heliodor or be like the other Edelberylle processed into gems while preserving mainly a bevelled edge. To meet the need for strong golden stones, pale yellow raw stones are increasingly using artificially produced radioactive radiation.
However, its thermal sensitivity makes high demands on the processing - starting from a temperature of 250 ° C occurs discoloration, so that the beryl turns pale.