Quartz is a hard mineral made of silica, silicon dioxide (SiO2), with its atoms linked in a continuous framework of silicon-oxygen tetrahedra. It is the second most common mineral or mineral group in the Earth's lithosphere, about 12 percent by mass, and a defining constituent of granite and other felsic igneous rocks. It is also very common in sandstone and shale, in schist, gneiss and quartzite, and in stream sediments, because it weathers less readily than other common minerals. Quartz defines hardness 7 on the Mohs scale, and at room temperature it is the trigonal alpha form, which changes abruptly at 573 degrees Celsius into the hexagonal beta form. Its varieties, several of them gemstones, have been the most commonly used minerals for jewelry and hardstone carving in Europe and Asia since antiquity.
Facts
Formation ClassFramework silicate, classified compositionally as an oxide mineral 1 Chemical FormulaSiO2, a continuous framework of silicon-oxygen tetrahedra 1 Hardness (Mohs)Quartz is the reference mineral that defines the value of 7 on the Mohs scale itself. Classification
Strunz Class Crystal SystemTrigonal (Rhombohedral) 1 UseWikipedia 'Quartz' states this use (or use-bearing statement); earth5 pass. UseIndustrial and Abrasive 2 Wikipedia 'Quartz' states this use (or use-bearing statement); earth5 pass. Connections
Associated With
Granite's own lead description names quartz as one of its main constituent minerals.
Source Granite (Wikipedia)
Quartz named as one of the three dominant minerals of most pegmatites.
Source Pegmatite (Wikipedia)
Quartz is the dominant, near-exclusive mineral of quartzite.
Source Quartzite (Wikipedia)
Quartz named directly as a predominant mineral of rhyolite.
Source Rhyolite (Wikipedia)
Quartz is the dominant framework mineral of sandstone.
Source Sandstone (Wikipedia)
Caused By
Source EBSCO Research Starters: Igneous processes, rocks, and mineral deposits
Additional Source Quartz (Wikipedia)Occurrence
Source EBSCO Research Starters: Hydrothermal solutions and mineralization
Additional Source Quartz (Wikipedia)Occurrence
Source Quartz (Wikipedia)
Classified As
Crystallizes In System
In Discipline
Source Mineral (Wikipedia)
In the Other Atlases
Mineral Species Of
Also in Divinity Atlas: of this mineral species.
Also in Divinity Atlas: of this mineral species.
Also in Divinity Atlas: of this mineral species.
Also in Divinity Atlas: of this mineral species.
Also in Divinity Atlas: of this mineral species.
Also in Divinity Atlas: of this mineral species.
Also in Divinity Atlas: of this mineral species.
Also in Divinity Atlas: of this mineral species.
Also in Divinity Atlas: of this mineral species.
Sources
1. Quartz (Wikipedia)
Wikimedia FoundationLead section
Quartz is a hard mineral composed of silica (silicon dioxide).
Article text
Quartz can form as two distinct polymorphs depending on the temperature and pressure: α-quartz (also called low quartz or normal quartz) and β-quartz (also called quartz-beta or high quartz). α-quartz crystallizes in the trigonal crystal system, while β-quartz has greater symmetry and crystallizes in the hexagonal crystal system.
Caused By: Magmatism, Occurrence
While the majority of quartz crystallizes from molten magma, quartz also chemically precipitates from hot hydrothermal veins as gangue, sometimes with ore minerals such as gold, silver and copper.
Caused By: Hydrothermal Mineral Deposition, Occurrence
While the majority of quartz crystallizes from molten magma, quartz also chemically precipitates from hot hydrothermal veins as gangue, sometimes with ore minerals such as gold, silver and copper.
Caused By: Fractional Crystallization, Occurrence
Large crystals of quartz are found in magmatic pegmatites.
View the Source 2. Wikidata: Quartz
Wikidata Q43010
3. minerals.net: Quartz
minerals.netColor field
Colorless, white, purple, pink, brown, and black. Also gray, green, orange, yellow, blue, and red. Sometimes multicolored or banded .
Luster field
Vitreous . Transparent, colorless Quartz crystals from a few distinct localities may be adamantine .
View the Source 4. Geology.com: Quartz
Geology.comDescriptionQuote, Description
Quartz is the most abundant and widely distributed mineral found at Earth's surface.
Granite (Wikipedia)
Wikimedia FoundationAssociated With: Granite, Lead sectionQuote, Associated With: Granite, Lead section
is a coarse-grained (phaneritic) intrusive igneous rock composed mostly of quartz, alkali feldspar, mica and plagioclase.
Rhyolite (Wikipedia)
Wikimedia FoundationAssociated With: Rhyolite, Mineralogy sectionQuote, Associated With: Rhyolite, Mineralogy section
The mineral assemblage is predominantly quartz, sanidine, and plagioclase.
Pegmatite (Wikipedia)
Wikimedia FoundationAssociated With: Pegmatite, Lead sectionQuote, Associated With: Pegmatite, Lead section
Most pegmatites are composed of quartz, feldspar, and mica, having a similar silicic composition to granite.
Sandstone (Wikipedia)
Wikimedia FoundationAssociated With: Sandstone, Composition sectionQuote, Associated With: Sandstone, Composition section
Quartz framework grains are the dominant minerals in most clastic sedimentary rocks; this is because they have exceptional physical properties, such as hardness and chemical stability.
Quartzite (Wikipedia)
Wikimedia FoundationAssociated With: Quartzite, Lead sectionQuote, Associated With: Quartzite, Lead section
Quartzite is a very hard rock composed predominantly of an interlocking mosaic of quartz crystals.
EBSCO Research Starters: Hydrothermal solutions and mineralization
EBSCO Research StartersCaused By: Hydrothermal Mineral Deposition, Hydrothermal deposit types and gangue mineralsQuote, Caused By: Hydrothermal Mineral Deposition, Hydrothermal deposit types and gangue minerals
Quartz is the most common nonore, or gangue, mineral deposited.
EBSCO Research Starters: Igneous processes, rocks, and mineral deposits
EBSCO Research StartersCaused By: Fractional Crystallization, Pegmatites and hydrothermal fluidsQuote, Caused By: Fractional Crystallization, Pegmatites and hydrothermal fluids
The high water content of pegmatite fluids, some of it occurring as vapor, allows minerals such as quartz, feldspar, and mica to grow to enormous sizes, the largest of which are on the order of railway boxcars.
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