mineral

Quartz (Iron-stained or Chalcedony varieties)

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: Translucent to opaque, varying from off-white to orange-brown; Luster: Vitreous to waxy; Crystal structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65

Hardness: 7 on Mohs scale
Luster: Vitreous to waxy

Identified July 11, 2026More mineral →

Explore Quartz (Iron-stained or Chalcedony varieties) in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Formation & geological history

Commonly forms in hydrothermal veins, as precipitates from silica-rich groundwater, or as a component of igneous and metamorphic rocks. These specific specimens appear to be weathered nodules or river-worn fragments from sedimentary deposits.

Uses & applications

Primarily used for lapidary work, jewelry (when high quality), and as a industrial source of silica for glass and electronics. These specific pieces are mainly for personal collection or educational purposes.

Geological facts

Quartz is one of the most abundant minerals on Earth's crust. The brownish-orange tint in these specimens is typically caused by goethite or hematite (iron oxide) inclusions or surface staining.

Field identification & locations

Identify in the field by its inability to be scratched by a steel knife (hardness test) and its characteristic glass-like fracture. These are ubiquitous across North America and Europe in gravel pits, beaches, and mountain streams.

Other mineral specimens

See all

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

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