mineral
Amethyst geode fragment
Quartz, SiO₂, colored by trace iron; purple quartz crystals lining a geode cavity
AI-generated identification · may be incorrectVisible purple crystalline interior with a dark gray-brown outer rind. Quartz has Mohs hardness 7, vitreous luster, and a trigonal crystal structure; the specimen appears to be a small cut or broken geode section.
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Physical properties
Visible purple crystalline interior with a dark gray-brown outer rind. Quartz has Mohs hardness 7, vitreous luster, and a trigonal crystal structure; the specimen appears to be a small cut or broken geode section.
Formation & geological history
Amethyst crystals formed as silica-rich fluids deposited quartz inside a cavity in volcanic rock; iron impurities and natural radiation produced the purple color. The exact age and locality cannot be determined from the image.
Uses & applications
Amethyst is used in jewelry, ornaments, and mineral collections; geode fragments are commonly displayed as curiosities.
Geological facts
Amethyst is the purple variety of quartz, and its color can fade with prolonged exposure to strong sunlight.
Field identification & locations
Identify it by the purple quartz crystals and contrasting outer rind; notable sources include Brazil, Uruguay, and Zambia. The image does not establish provenance or gem quality.
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