gemstone
Agate
Silicon Dioxide (SiO2), microcrystalline quartz
AI-generated identification · may be incorrectMohs hardness of 6.5 to 7; displays banded colors including green, yellow, and brown; waxy to vitreous luster; cryptocrystalline structure.
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Physical properties
Mohs hardness of 6.5 to 7; displays banded colors including green, yellow, and brown; waxy to vitreous luster; cryptocrystalline structure.
Formation & geological history
Forms by the deposition of silica from groundwater in cavities of igneous and sedimentary rocks over millions of years.
Uses & applications
Widely used for making tumbled stones, beads, jewelry, decorative carvings, and ornaments.
Geological facts
Agate has been used for amulets and ornamentation since ancient Egyptian and Greek civilizations.
Field identification & locations
Identify by its distinctive concentric color banding and hardness that scratches glass; found globally, especially in Brazil, India, and the USA.
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