Quartz Family
Current inventory:  0 gems
 

  
Quartz is named from the German word quarz (of uncertain origin). The word crystal was originally used only for Quartz and is from the Greek word krystallos, meaning ice, because the Greeks thought the gods had created an unnatural frost that froze ice hard forever.

Prehistoric Discovery; IMA status: Valid (pre-IMA; Grandfathered)

Chemistry

Chemical Formula:

SiO₂

Silicon Dioxide

Molecular Weight:

60.08 gm

Composition:

Silicon

46.74 %

Be

100.00 %

SiO₂

Oxygen

53.26 %

O

100.00 %

100.00 %

= TOTAL OXIDE

Classification

Mineral Classification:

Oxides

Strunz 8th Ed. ID:

4/D.01-10

Nickel-Strunz 10th Ed. ID:

4.DA.05

4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
D : Metal: Oxygen = 1:2 and similar
A : With small cations: Silica family
 

Related to:

Polymorph of Coesite, Cristobalite, Mogánite, Seifertite, Stishovite, Tridymite. Isostructural with Berlinite.
 

Varieties: 

Abakusz-kö, Agate, Agate-Jasper, Agatized coral, Amarillo Stone, Amberine, Amethyst, Ametrine, Apricotine, Arkansas Candle, Aventurine, Azurchalcedony, Babel-Quartz, Ball Jasper, Basanite, Bayate, Beekite, Binghamite, Bloodstone, Blue Chalcedony, Blue Lace Agate, Blue Quartz, Botswana Agate, Brazilian Pebble, Brecciated Agate, Bristol Diamonds, Buhrstone, Bull Quartz, Burnt Amethyst, Cactus Quartz, Cape May Diamonds, Capped Quartz, Carnelian, Chalcedony, Chrome-Chalcedony, Chrysojasper, Citrine, Clear Lake Diamonds, Cloud Agate, Cotterite, Crazy Lace Agate, Creolite, Cubosilicite, Dallasite, Damsonite, Darlingite, Dendritic Agate, Diackethyst, Dragonite, Egyptian Jasper, Eisenkiesel, El Doradoite, Enhydro Agate, Eye Agate, Fairburn Agate, Fensterquarz, Ferruginous Quartz, Fire Agate, Fortification Agate, Fossil Agate, Gwindel, Haema-ovoid-agates, Hair Amethyst, Haytorite, Hedgehog Stone, Herbeckite, Herkimer Diamond, Herradura Diamonds, Iris Agate, Iris Quartz, Irnimite, Jacinto de Compostela Quartz, Jasper, Keystonite Chalcedony, Kinradite, Laguna Agate, Lake County Diamonds, Lake Superior Agate, Landscape Agate, Lithium Quartz, Marmaroscher Diamanten, Mexican Lace Agate, Milky Quartz, Mocha Stone, Moss Agate, Mutzschen Diamonds, Myrickite, Nipomo Agate, Oil Quartz, Onyx, Owyhee Jasper, Pastelite, Pietersite, Pigeon Blood Agate, Plasma, Plume Agate, Prase, Prase-malachite, Prasiolite, Pseudocubic Quartz, Quartzine, Quetzalitztli, Riband Agate
 

Synonyms:

α-Quartz, Alpha-Quartz, Azetulite, Azeztulite, β-Quartz (of Geophys. Lab), Brazillian Pebble, Conite (of Macculloch), Cornish Diamond, Konilite, Lemurian Seed Crystal, Lodolite, Low Quartz, Mexican Diamond, Quartz-alpha, Quartz-α, Quertz

Crystal Data

Crystallography:

Trigonal - Trapezohedal

Crystal Habit:

Widely variable; but typically long prismatic with steep pyramidal terminations, but may be short prismatic to nearly bipyramidal; fibrous (Agate & Chalcedony)

Twinning:

Very common, penetration twins on the Dauphiné law, about [0001], and the Brazil law, with [1120] as contact plane; contact twins on the Japan law, with [1122] as contact plane, may be repeated; and several other laws.

Physical Properties

Cleavage:

[0110] Indistinct

Fracture:

Conchoidal

Tenacity:

Brittle, tough when massive

Moh's Hardness:

7.0

Density:

2.60 - 2.65 (g/cm³)

Luminescence:

Fluorescent; Shortwave UV = yellow-orange, Longwave UV = yellow-orange.
May be Triboluminescent

Radioactivity:

Not Radioactive

Other:

Piezoelectric and Pyroelectric and may be Triboluminescent

Optical Properties

Color:

Colorless, white, gray, and many shades of violet, purple, yellow, orange, red, brown, pink, green, blue and black

Transparency:

Transparent to nearly Opaque

Luster:

Vitreous, waxy to dull when massive

Refractive Index:

1.543 - 1.554  Uniaxial ( + )

Birefringence:

0.0090

Dispersion:

0.013 (low)

Pleochroism:

Quartz: none; Amethyst: weak; Citrine: weak; Rose Quartz: strong

Occurances

Geological Setting:

In hydrothermal veins, epithermal to alpine; characteristic of granites and granite pegmatites; in sandstones and quartzites, less abundant in other rock types; in hydrothermal metal deposits. Common in carbonate rocks; a residual mineral in soils and sediments.

Common Associations:

Calcite, Chlorite, Epidote, Feldspars, Fluorite, Micas, Zeolites, many other species.

Type Locality:

n/a

Year Discovered:

Prehistoric

View mineral photos:

Quartz Mineral Photos and Locations

More Information

Mindat.org
Webmineral.com

Quartz is one of the most common minerals on Earth. It is composed of silicon and oxygen, the two most abundant elements in the crust of the Earth. Quartz comes in many colors including purple/violet (Amethyst); yellow and purple (Ametrine); yellow/orange (Citrine); pink (Rose Quartz); brown (Smoky Quartz); green (Prasiolite) and colorless (Rock Crystal). The various colors are due to trace elements added to the basic Silicon Dioxide formula. Quartz also has many attractive and collectable inclusions (see below) created by the addition of other minerals such as Actinolite,  Gilalite, Lepidocrocite, Pyrite, Rutile, Tourmaline and many others. Quartz catseyes and stars are also available and are created by the presence of fine asbestos or rutile fibers. Quartz gems have been faceted in enormous sizes. The Smithsonian Institute (SI) has a perfect sphere of flawless Burmese Rock Crystal that is 12.75 inch in diameter and weighs 107 pounds. SI also has a 7000 carat faceted Quartz, a 2258 carat Brazilian Citrine, a 4500 carat Smoky Quartz and a 1362 carat Brazilian Amethyst!
 

Quartz varieties

 

Inclusions in Quartz

 

  
Quartz crystals grow in many different environments along with many different minerals. These minerals, as well as gas bubbles, water and petroleum solutions, can become enclosed or trapped within the growing Quartz crystals. These "inclusions" have become a very popular gem collecting category with incredible beauty and variety. Below are some of the many types of inclusions found in Quartz gems.

  
Quartz Family varieties