mineral
Smoky Quartz Pebble
Silicon Dioxide (SiO2)
Hardness: 7 on Mohs scale; Color: Grayish-brown to smoky gray; Luster: Vitreous/glassy; Crystal Structure: Trigonal/Hexagonal; Conchoidal fracture; Specific gravity: 2.65
- Hardness
- 7 on Mohs scale
- Color
- Grayish-brown to smoky gray
- Luster
- Vitreous/glassy
Identified More mineral →
Explore Smoky Quartz Pebble in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 7 on Mohs scale; Color: Grayish-brown to smoky gray; Luster: Vitreous/glassy; Crystal Structure: Trigonal/Hexagonal; Conchoidal fracture; Specific gravity: 2.65
Formation & geological history
Forms in igneous and metamorphic rocks (granite, gneiss) through crystallization from magma or hydrothermal pulses. The smoky color is usually due to natural irradiation of aluminum-bearing quartz.
Uses & applications
Used for jewelry, ornamental stones, and metaphysical collecting. Also used in electronics as a piezoelectric component.
Geological facts
The smoky color is caused by trace aluminum and exposure to natural radiation from surrounding radioactive elements like potassium or uranium. High heat can cause the color to disappear or turn yellow.
Field identification & locations
Identified by its waxy-to-glassy luster, lack of cleavage, and translucency. Common in riverbeds and mountainous regions like the Alps, Brazil, and the USA.
More like this
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
Potassium Feldspar (Orthoclase)
Orthoclase (KAlSi3O8)
mineral
Gypsum (variety Selenite or Alabaster)
Calcium sulfate dihydrate (CaSO4·2H2O)
Mineral
Epidote
Epidote | Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)
metamorphic