Smoky quartz

Mineral, quartz variety

Smoky quartz

General
Category| Silicate minerals
Formula
(repeating unit)| SiO2
Strunz classification| 04.DA.05
Dana classification| 75.01.03.01
Crystal system| α-quartz: trigonal trapezohedral class 3 2; β-quartz: hexagonal 622[1]
Space group| Trigonal 32
Unit cell| a = 4.9133 Å, c = 5.4053 Å; Z=3
Identification
Colour| Brown to grey, opaque
Crystal habit| 6-sided prism ending in 6-sided pyramid (typical), drusy, fine-grained to microcrystalline, massive
Twinning| Common Dauphine law, Brazil law and Japan law
Cleavage| {0110} Indistinct
Fracture| Conchoidal
Tenacity| Brittle
Mohs scale hardness| 7 – lower in impure varieties (defining mineral)
Lustre| Vitreous – waxy to dull when massive
Streak| White
Diaphaneity| Transparent to nearly opaque
Specific gravity| 2.65; variable 2.59–2.63 in impure varieties
Optical properties| Uniaxial (+)
Refractive index| nω = 1.543–1.545
nε = 1.552–1.554
Birefringence| +0.009 (B-G interval)
Pleochroism| weak, from red-brown to green-brown
Melting point| 1670 °C (β tridymite) 1713 °C (β cristobalite)[1]
Solubility| Insoluble at STP; 1 ppmmass at 400 °C and 500 lb/in2 to 2600 ppmmass at 500 °C and 1500 lb/in2[1]
Other characteristics| lattice: hexagonal, Piezoelectric, may be triboluminescent, chiral (hence optically active if not racemic)
References| [2][3][4][5]

Smoky quartz is a brownish grey, translucent variety of quartz that ranges in clarity from almost complete transparency to an almost-opaque brownish-gray or black crystals.[6] The color of smoky quartz is produced when natural radiation, emitted from the surrounding rock, activates color centers around aluminum impurities within the crystalline quartz. [7]

## Varieties

[edit]

Morion is a very dark brown to black opaque variety. Morion is the German, Danish, Spanish and Polish synonym for smoky quartz.[8] The name is from a misreading of mormorion in Pliny the Elder.[9]

Cairngorm is a variety of smoky quartz found in the Cairngorm Mountains of Scotland.[10] It usually has a smoky yellow-brown colour, though some specimens are greyish-brown. It is used in Scottish jewellery and as a decoration on kilt pins and the handles of sgianan-dubha (anglicised: sgian-dubhs or skean dhu).[11] The largest known cairngorm crystal is a 23.6 kg (52 lb) specimen kept at Braemar Castle.[citation needed]

## Uses

[edit]

Smoky quartz is common and was not historically important, but in recent times it has become a popular gemstone, especially for jewelry.[12]

Sunglasses, in the form of flat panes of smoky quartz, were used in China in the 12th century.[13]

## See also

[edit]

* List of minerals

## References

[edit]

1. ^ a b c Deer, W. A., R. A. Howie and J. Zussman, An Introduction to the Rock Forming Minerals, Logman, 1966, pp. 340–355 ISBN 0-582-44210-9
2. ^ Anthony, John W.; Bideaux, Richard A.; Bladh, Kenneth W.; Nichols, Monte C. (eds.). "Quartz". Handbook of Mineralogy (PDF). Vol. III (Halides, Hydroxides, Oxides). Chantilly, VA, US: Mineralogical Society of America. ISBN 0962209724.
3. ^ Quartz. Mindat.org. Retrieved on 2013-03-07.
4. ^ Quartz. Webmineral.com. Retrieved on 2013-03-07.
5. ^ Hurlbut, Cornelius S.; Klein, Cornelis (1985). Manual of Mineralogy (20 ed.). ISBN 0-471-80580-7.
6. ^ "Smoky Quartz: Smoky Quartz mineral information and data".
7. ^ "Smoky Quartz: A transparent brown gem & gem material".
8. ^ http://www.mindat.org/min-6270.html Morion on Mindat
9. ^ New Oxford American Dictionary (2nd ed., 2005), p. 1102.
10. ^ Shaw, Philip; Thompson, Des B. A. (12 June 2006). The Nature of the Cairngorms: Diversity in a Changing Environment. The Stationery Office. p. 22\. ISBN 978-0-11-497326-1.
11. ^ Chisholm, Hugh, ed. (1911). "Cairngorm" . Encyclopædia Britannica. Vol. 4 (11th ed.). Cambridge University Press. p. 952.
12. ^ "The Gemstone Smoky Quartz". minerals.net. Retrieved 14 December 2015.
13. ^ Joseph Needham, Science & Civilisation in China (Cambridge, England: Cambridge University Press, 1962), volume IV, part 1, page 121. Needham states that dark glasses were worn by Chinese judges to hide their facial expressions during court proceedings.

* Holden, Edward (1925). "The Cause of Color in Smoky Quartz and Amethyst" in American Mineralogist, vol. 9, pp. 203–252

## External links

[edit]

* Media related to Smoky quartz at Wikimedia Commons
* Works related to EB1911:Cairngorm at Wikisource
* Mineral Galleries - smoky quartz

* v
* t
* e

Silica minerals

Crystalline|

* Coesite
* Cristobalite
* Keatite
* Moganite
* Quartz
* Seifertite
* Stishovite
* Tridymite

Cryptocrystalline|

* Chalcedony
* Chert
* Flint
* Jasper

Amorphous|

* Fulgurite
* Lechatelierite
* Opal

Miscellaneous|

* Tiger's eye
* Aqeeq

Notable varieties|

| Chalcedony|

* Agate
* Carnelian
* Chrome chalcedony
* Chrysoprase
* Heliotrope
* Moss agate
* Onyx

|

Opal|

* Fiorite
* Geyserite

Quartz|

* Amethyst
* Ametrine
* Herkimer diamond
* Smoky quartz
* Shocked quartz
* Prasiolite

Minerals portal

* v
* t
* e

Jewellery

Forms|

* Anklet
* Barrette
* Belly chain
* Belt buckle
* Bindi
* Bolo tie
* Bracelet
* Brooch
* Chatelaine
* Collar pin
* Crown
* Cufflink
* Earring
* Ferronnière
* Genital
* Lapel pin
* Necklace
* Neck ring
* Pectoral
* Pendant
* Ring
* Tiara
* Tie chain
* Tie clip
* Tie pin
* Toe ring
* Watch
* pocket
* strap

Making|

| People|

* Bench jeweler
* Clockmaker
* Goldsmith
* Jewellery designer
* Lapidarist
* Silversmith
* Watchmaker

|

Processes|

* Carving
* Casting
* centrifugal
* lost-wax
* vacuum
* Enameling
* Engraving
* Filigree
* Kazaziye
* Metal clay
* Plating
* Polishing
* Repoussé and chasing
* Soldering
* Stonesetting
* Wire sculpture
* Wire wrapped jewelry

Tools|

* Draw plate
* File
* Hammer
* Mandrel
* Pliers

Materials|

| Precious metals|

* Gold
* Palladium
* Platinum
* Rhodium
* Silver

|

Precious metal alloys|

* Britannia silver
* Colored gold
* Crown gold
* Electrum
* Shakudō
* Shibuichi
* Sterling silver
* Argentium
* Tumbaga

Base metals|

* Brass
* Bronze
* Copper
* Mokume-gane
* Nickel silver (alpacca)
* Pewter
* Pinchbeck
* Stainless steel
* Titanium
* Tungsten

Mineral gemstones|

* Agate
* Amazonite
* Amethyst
* Aventurine
* Beryl (red)
* Carnelian
* Chrysoberyl
* Chrysocolla
* Diamond
* Diopside
* Emerald
* Fluorite
* Garnet
* Howlite
* Jade
* Jasper
* Kyanite
* Labradorite
* Lapis lazuli
* Larimar
* Malachite
* Marcasite
* Moonstone
* Obsidian
* Onyx
* Opal
* Peridot
* Prasiolite
* Quartz (smoky)
* Ruby
* Sapphire
* Sodalite
* Spinel
* Sunstone
* Tanzanite
* Tiger's eye
* Topaz
* Tourmaline
* Turquoise
* Variscite
* Zircon

Organic gemstones|

* Abalone
* Amber
* Ammolite
* Copal
* Coral
* Black
* Precious
* Ivory
* Jet
* Nacre
* Operculum
* Pearl
* Tortoiseshell

Other natural objects|

* Bezoar
* Bog-wood
* Ebonite (vulcanite)
* Gutta-percha
* Hair
* Shell
* Spondylus shell
* Toadstone

Terms|

* Art jewelry
* Carat (mass)
* Carat (purity)
* Finding
* Fineness

Related topics
Body piercing
Fashion
Gemology
Metalworking
Phaleristics
Wearable art

This article about a specific mineral or mineraloid is a stub. You can help Wikipedia by expanding it.

|

* v
* t
* e

*[v]: View this template
*[t]: Discuss this template
*[e]: Edit this template