Mineral

Quartz and Mixed Gravel

Silicon Dioxide (SiO2) with minor impurities

Hardness of 7 on the Mohs scale, colors range from white/milky to gray and tan, vitreous to dull luster, hexagonal crystal system (though rounded here), no cleavage, conchoidal fracture

Identified May 27, 2026More mineral →

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Physical properties

Hardness of 7 on the Mohs scale, colors range from white/milky to gray and tan, vitreous to dull luster, hexagonal crystal system (though rounded here), no cleavage, conchoidal fracture

Formation & geological history

Formed from cooling of silica-rich magma or precipitation in hydrothermal veins; these specimens are sub-angular to rounded, suggesting transport/erosion by water in fluvial or glacial environments.

Uses & applications

Common quartz and gravel are used extensively in the construction industry for concrete, road base, and as decorative landscaping stones.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. One blue fragment appears to be a dyed pebble or a small piece of tumbled turquoise-colored stone used in decorative gravel.

Field identification & locations

Identify in the field by its hardness (it will easily scratch glass) and lack of cleavage. These are common surface finds in riverbeds, driveways, and suburban soil.

Other mineral specimens

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Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

sedimentary

Epidote

Epidote | Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)

metamorphic

Nephrite Jade

Nephrite

Mineral/Rock

Banded Gneiss (River Rock/Pebble)

Gneiss (specifically a banded variety often found as a river rock)

Metamorphic Rock

Biotite Schist

Biotite-rich Schist [K(Mg,Fe)3AlSi3O10(F,OH)2]

metamorphic

Green Apatite on Albite

Fluorapatite [Ca5(PO4)3F] on Albite [Na(AlSi3O8)]

mineral