Galena diode. Making such wireless receivers was a popular home hobby in Britain and other European countries during the 1930s. Scientists associated with the investigation of the diode effect are Karl Ferdinand Braun and Jagadish Bose. In modern wireless communication systems, galena detectors have been replaced by more reliable semiconductor devices. Galena Galena, also called lead glance, is the natural mineral form of lead(II) sulfide. It is the most important ore of lead and an important source of silver. Galena is one of the most abundant and widely distributed sulfide minerals. It crystallizes in the cubic crystal system often showing octahedral
Ore Mountains mining in the southern forelands of the Ore Mountains. Europe's largest deposits of lithium-bearing mica zinnwaldite in Cínovec, a Czech village between town of Dubí and the border with Germany which gave its old German name Zinnwald to the mineral, are expected to be mined starting 2019 (as of June 2017). When several Ore Mountain passes were upgraded into "chaussees" in the 19th century, and the Upper Ore Mountains were accessed by the railway, tourism began to develop. One of the early promoters of tourism in the Ore Mountains was Otto Delitsch. In 1907, a memorial was erected to him