mineral
Quartz (Grain)
Silicon Dioxide (SiO2)
Hardness: 7 (Mohs scale), Color: Colorless to white (transparent), Luster: Vitreous (glassy), Crystal Structure: Trigonal/Hexagonal, Cleavage: None (conchoidal fracture), Specific Gravity: 2.65
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Physical properties
Hardness: 7 (Mohs scale), Color: Colorless to white (transparent), Luster: Vitreous (glassy), Crystal Structure: Trigonal/Hexagonal, Cleavage: None (conchoidal fracture), Specific Gravity: 2.65
Formation & geological history
Quartz forms in all types of geological environments: igneous (crystallizing from cooling magma), sedimentary (as resistant grains in sand/sandstone), and metamorphic (recrystallized in rocks like quartzite). This specific grain appears to be a detrital grain from weathered rock.
Uses & applications
Used in glass manufacturing, electronics (piezoelectric properties), abrasives, construction sand, and as a gemstone when found in larger crystals.
Geological facts
Quartz is the second most abundant mineral in Earth's continental crust. It is highly resistant to chemical and physical weathering, which is why it is the primary component of most beach sand.
Field identification & locations
Identified in the field by its hardness (scratches glass), glass-like appearance, and lack of cleavage. Common in riverbeds, beaches, and various rock outcrops worldwide.
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Other mineral specimens
Sandstone (with potential mineral staining/concretions)
Arenite (SiO2 based)
sedimentary
Sandstone with Mineral Veining or Crust
Sedimentary Sandstone (mostly SiO2 with Fe2O3 tinting)
sedimentary
Schist
Schist
Metamorphic
Epidote
Epidote | Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)
metamorphic
Gypsum (variety Selenite or Alabaster)
Calcium sulfate dihydrate (CaSO4·2H2O)
Mineral
Nephrite Jade
Nephrite
Mineral/Rock