igneous
Quartz with Mafic Inclusions
Silicon Dioxide (SiO2) with host igneous matrix
Hardness: 7 (Quartz part), Color: White/Tan and dark gray/black, Luster: Vitreous to dull, Structure: Crystalline to microcrystalline, Specific Gravity: 2.65
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Physical properties
Hardness: 7 (Quartz part), Color: White/Tan and dark gray/black, Luster: Vitreous to dull, Structure: Crystalline to microcrystalline, Specific Gravity: 2.65
Formation & geological history
Formed through hydrothermal processes or within igneous intrusions where silica-rich fluids crystallized alongside or within darker mafic minerals like basalt or gabbro.
Uses & applications
Primarily used as a decorative landscape stone, gravel, or a common specimen for educational purposes and novice collectors.
Geological facts
Quartz is one of the most abundant minerals on Earth. This specific specimen shows a contact zone between two different mineral phases, likely tumbled by water action in a stream or beach.
Field identification & locations
Identify by its ability to scratch glass (quartz) and the distinct color contrast between the felsic (light) and mafic (dark) components. Commonly found in riverbeds and glacial deposits.
