mineral
Slag Glass
Silicon dioxide with impurities
Hardness 5-6, vitreous luster, conchoidal fracture, amorphous structure, various colors (often green, blue, brown, or clear)
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Physical properties
Hardness 5-6, vitreous luster, conchoidal fracture, amorphous structure, various colors (often green, blue, brown, or clear)
Formation & geological history
Byproduct of smelting ore to purify metals or from glass manufacturing. Often found near old industrial sites.
Uses & applications
Sometimes collected for its appearance, occasionally used in lapidary work or as a decorative item.
Geological facts
Slag glass can often be mistaken for obsidian or other natural minerals. The color is typically determined by the metals and impurities present during the smelting process.
Field identification & locations
Identify by its conchoidal fracture, glassy luster, and the presence of spherical bubbles inside the material (which are absent in natural obsidian).
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