12 - Obsidian

Hello friends, Welcome to the Rock Repository at the Department of Geology, Shivaji Science College, Nagpur.

I am Obsidian, an igneous rock formed  from felsic lava, rich in lighter elements like silicon, oxygen, aluminium, sodium, and potassium. I am often found nestled within the confines of rhyolitic lava flows, renowned as obsidian flows. These flows boast a rich silica content, imparting them with a high viscosity.  I am a product of the Earth's fiery depths. Formed  when molten lava emerges from a volcano and swiftly cools upon exposure to the air, my formation is marked by minimal crystal growth. This swift cooling process leaves me with a smooth, glass-like appearance, preserving the memory of volcanic eruptions frozen in time. When coupled with rapid cooling, this unique environment gives rise to my distinctive feature: a natural glassy texture. My nature is that of resilience and sharpness; I am hard, brittle, and possess an amorphous structure, thus fracturing with razor-sharp edges. Throughout history, humans have used my qualities, crafting me into cutting and piercing tools. At times, I've even been enlisted in the realm of medical science, where I've served as experimental surgical scalpel blades.

Thank you for visiting.