Mineral Type - Quartz - All

Quartz is one of the most common minerals found in the Earth's crust. If pure, quartz forms colourless, transparent and very hard crystals with a glass-like lustre. A significant component of many igneous, metamorphic and sedimentary rocks, this natural form of silicon dioxide is found in an impressive range of varieties and colours.

Name

Quartz has been known and appreciated since pre-historic times. The most ancient name known is recorded by Theophrastus in about 300-325 BCE, κρύσταλλος or kristallos. The varietal names, rock crystal and bergcrystal, preserve the ancient usage. The root words κρύοσ signifying ice cold and στέλλειυ to contract (or solidify) suggest the ancient belief that kristallos was permanently solidified ice.

The earliest printed use of "querz" was anonymously published in 1505, but attributed to a physician in Freiberg, Germany, Ulrich Rülein von Kalbe (a.k.a. Rülein von Calw, 1527). Agricola used the spelling "quarzum" (Agricola 1530) as well as "querze", but Agricola also referred to "crystallum", "silicum", "silex", and silice". Tomkeieff (1941) suggested an etymology for quartz: "The Saxon miners called large veins - Gänge, and the small cross veins or stringers - Querklüfte. The name ore (Erz, Ertz) was applied to the metallic minerals, the gangue or to the vein material as a whole. In the Erzgebirge, silver ore is frequently found in small cross veins composed of silica. It may be that this ore was called by the Saxon miners 'Querkluftertz' or the cross-vein-ore. Such a clumsy word as 'Querkluftertz' could easily be condensed to 'Querertz' and then to 'Quertz', and eventually become 'Quarz' in German, 'quarzum' in Latin and 'quartz' in English." Tomkeieff (1941, q.v.) noted that "quarz", in its various spellings, was not used by other noted contemporary authors. "Quarz" was used in later literature referring to the Saxony mining district, but seldom elsewhere.

Gradually, there were more references to quartz: E. Brown in 1685 and Johan Gottschalk Wallerius in 1747. In 1669, Nicolaus Steno (Niels Steensen) obliquely formulated the concept of the constancy of interfacial angles in the caption of an illustration of quartz crystals. He referred to them as "cristallus" and "crystallus montium".

Tomkeieff (1941) also noted that Erasmus Bartholinus (1669) used the various spellings for "crystal" to signify other species than quartz and that crystal could refer to other "angulata corpora" (bodies with angles): "In any case in the second half of the XVIIIth century quartz became established as a name of a particular mineral and the name crystal became a generic term synonymous with the old term 'corus angulatum'."

Physical Properties

Lustre: Vitreous
Transparency: Transparent, Translucent
Colour: Colourless, purple, rose, red, black, yellow, brown, green, blue, orange, etc
Streak: White
Hardness: 7 on Mohs scale
Tenacity: Brittle
Cleavage: Poor/Indistinct. The rhombohedral cleavage r{1011} is most often seen, there are at least six others reported
Fracture: Conchoidal. Tough when massive
Density: 2.65 – 2.66 g/cm3 (Measured) 2.66 g/cm3 (Calculated)

Chemical Properties

Formula: SiO2
Elements listed: O, Si
Common Impurities: H,Al,Li,Fe,Ti,Na,Mg,Ge,etc

Age Distribution

Recorded ages: Phanerozoic : 279 ± 3 Ma to 55.7 Ma - based on 7 recorded ages

Crystallography

Crystal System: Trigonal
Class (H–M): 3 2 – Trapezohedral
Space Group: P31 2 1

Synonyms

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

Varieties

"Herkimer-style" Quartz, Agate, Agate-Jasper, Agatized coral, Amarillo Stone, Amberine, Amethyst, Ametrine, Apricotine, Aquaprase, Arkansas Candle, Aventurine, Azurchalcedony, Babel-Quartz, Ball Jasper, Bayate, Beekite, Binghamite, Bird's Eye Agate, Blue Chalcedony, Blue Lace Agate, Blue Quartz, Botswana Agate, Brecciated Agate, Buhrstone, Bull Quartz, Burnt amethyst, Cactus Quartz, Cape May Diamond, Capped Quartz, Carnelian, Chalcedony, Chrome-Chalcedony, Chrysojasper, Citrine, Clear Lake Diamond, Cloud Agate, Cotterite, Crazy Lace, Agate, Creolite, Cubosilicite, Dallasite, Damsonite, Darlingite, Dendritic Agate, Diackethyst, Dotsero Diamond, Dragonite, Egyptian Jasper, Eisenkiesel, El Doradoite, Enhydro Agate, Eye Agate, Faden Quartz, Fairburn Agate, Fensterquarz, Ferruginous Quartz, Fire Agate, Fortification Agate, Fossil Agate, Gwindel Haema-ovoid-agates, Hair Amethyst, Haytorite, Herbeckite, Iris Agate, Iris Quartz, Jacinto de Compostela Quartz, Jasper, Keystonite Chalcedony, Kinradite, Laguna Agate, Lake Superior Agate, Landscape Agate, Lithium Quartz, 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, Riband Jasper, Rock Crystal, Rose Quartz, Rutilated Quartz, Sagenite (of Kunz), Sard, Sardonyx, Sceptre Quartz, Schwimmstein, Seftonite, Shocked Quartz, Smoky Quartz, Snakeskin Agate, Star Quartz, Suttroper Quarz, Vogelaugenjaspis, Wilkite, and Youngite

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