Lava destined to become obsidian cools rapidly once on the surface and, thanks to its viscous nature, is also below the point at which crystals within can grow to become sizeable – this makes ...

Lava destined to become obsidian cools rapidly once on the surface and, thanks to its viscous nature, is also below the point at which crystals within can grow to become sizeable – this makes ...

Obsidian is a popular crystal, prized for its deep black colour and glassy texture. It's formed from volcanic lava that cools rapidly, resulting in its smooth, often shiny appearance.