| It is not possible to write a chapter about the mineral galena without looking at the history of lead and silver to name two of the most important raw materials and materials of humanity. How long people processed galena as main ore for the production of lead is unknown. As lead inter alia used as a ... moreIt is not possible to write a chapter about the mineral galena without looking at the history of lead and silver to name two of the most important raw materials and materials of humanity. How long people processed galena as main ore for the production of lead is unknown. As lead inter alia used as an additive to various melts (e.g. to bronze and the salt-cementation process for gold extraction) one can assume that the properties of this mineral were known before 3000 BC. Other sources speak of a history of lead about 7000-9000 years BC back. |
| This portrait explains the background to the most fascinating natural events on Earth, how are volcanoes build and what causes eruptions, lava flows and lahars. A rich picture book with some stunning shots invites you to dive into the fascinating world of magmatic phenomena. (Article in german) ... moreThis portrait explains the background to the most fascinating natural events on Earth, how are volcanoes build and what causes eruptions, lava flows and lahars. A rich picture book with some stunning shots invites you to dive into the fascinating world of magmatic phenomena. (Article in german) |