igneous
Slag
Anthropogenic silicate slag
AI-generated identification · may be incorrectHardness varies from 5 to 6 on the Mohs scale depending on composition. Exhibits a glassy to dull luster with vesicular texture and irregular colors including black, brown, and red.
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Physical properties
Hardness varies from 5 to 6 on the Mohs scale depending on composition. Exhibits a glassy to dull luster with vesicular texture and irregular colors including black, brown, and red.
Formation & geological history
Formed as a byproduct of smelting ore to purify metals like iron and copper, occurring wherever historical or modern metal processing takes place.
Uses & applications
Used locally as road aggregate, railroad ballast, and in construction fill, or collected as a historical artifact.
Geological facts
Slag is often mistaken for volcanic rock like scoria or basalt due to its bubbly, vesicular texture. Historical slag dumps can provide valuable archaeological insights into ancient metallurgy.
Field identification & locations
Identified by its frothy or vesicular structure containing gas bubbles, combined with an unusually heavy weight and glassy fracture. Common near old mining and smelting sites worldwide.
