Obsidian rock. Obsidian is an igneous rock formed by the rapid cooling of volcanic magma or lava which contains granite. Obsidian has a glass-like structure because it contains high levels of silica,the basic component of glass. The rock's black colour is due to the presence of small amounts of iron. Once used by Stone Age humans to make tools,obsidian is now used industrially as raw material for rock wool. Photographed in Iceland | |
Licence : | Droits gérés |
Crédit: | Science Photo Library / Wiersma, Dirk |
Taille de l’image : | 3439 px × 5083 px |
Model Release : | Non requis |
Property Release : | Non requis |
Restrictions : | - |