Vein
Definition
A sheet-like deposit of minerals that fills a fracture or crack in a host rock, often formed by hydrothermal fluids.
Example
Gold is often found in quartz veins that cut through surrounding rock.
Nature's Plumbing System
A vein is a distinct sheet-like body of crystallized minerals within a rock. Veins form when mineral-rich fluids (often hydrothermal water) flow through open fractures in the Earth's crust. As the water cools or the pressure drops, minerals precipitate out of the solution, filling the crack. Veins can be millimeters thin or many meters wide.
Economic Importance
Veins are the primary source of many precious metals. Gold, silver, and copper are often found in Quartz veins (lodes). Miners chase these veins deep underground. Sometimes, the vein does not fill completely, leaving open pockets called <strong>vugs</strong> where beautiful, perfect crystals can grow without being crowded.