ADRIENNE HART-DAVIS / SCIENCE PHOTO LIBRARY ADRIENNE HART-DAVIS / SCIENCE PHOTO LIBRARY
Snowflake obsidian. Pebbles of weathered snowflake obsidian rock lying on sand. Obsidian is an igneous volcanic rock formed by the rapid cooling of granitic magma. It 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. Snowflake obsidian contains inclusions of white radial cristobalite clusters. Cristobalite is a form of quartz. These pebbles have been eroded and weathered in a fluvial environment into their smooth, polished shapes. Once used by Stone Age humans to make tools, obsidian is now used industrially as raw material for rock wool.
Model release not required. Property release not required.