mineral
Quartz (Milky/Common)
Silicon Dioxide (SiO2)
Hardness: 7 (Mohs scale), Color: White to off-white, Luster: Vitreous to greasy, Crystal structure: Trigonal/Hexagonal, Cleavage: None (conchoidal fracture), Specific Gravity: 2.65
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Physical properties
Hardness: 7 (Mohs scale), Color: White to off-white, Luster: Vitreous to greasy, Crystal structure: Trigonal/Hexagonal, Cleavage: None (conchoidal fracture), Specific Gravity: 2.65
Formation & geological history
Formed through the cooling of silica-rich magma or from hydrothermal veins. It is found in all types of geological environments and can date back billions of years depending on the host rock formation.
Uses & applications
Used in the manufacture of glass, electronics (piezoelectric properties), abrasives, and as a component in concrete and mortar. It is also collected by hobbyists.
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 often remains as pebbles or sand even after other minerals have eroded.
Field identification & locations
Identify by its hardness (it will scratch glass and steel) and lack of cleavage planes. Common in riverbeds, mountains, and desert sands globally.
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Sandstone (with potential mineral staining/concretions)
Arenite (SiO2 based)
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
Banded Gneiss (River Rock/Pebble)
Gneiss (specifically a banded variety often found as a river rock)
Metamorphic Rock