How are crystals made?


Famous Crystals I Have Known

Crystal Gayle, Crystal Bernard, Crystal the Monkey -- no, we don't mean any of those. When we speak of famous crystals we are, of course, referring to bling. Ice. Rocks. Fist sparklers.

Jewels.

Gemstones are crystals with a certain extra something. Call it pizzazz. Although we tend to think of them as individual rocks, many gemstones arise from the same minerals. The only differences between them are the structural idiosyncrasies and mineral impurities that imbue them with their trademark colors.

Rubies and sapphires are both types of corundum (crystalline aluminum oxide, or alumina), but while ruby's luscious reds derive from tiny amounts of chromium that partially replace aluminum in the crystal structure, sapphire's brilliant blues come from iron and titanium impurities [sources: Encyclopaedia Britannica; Kay].

Amethyst and citrine are different versions of quartz (crystalline silicon dioxide aka silica), which is naturally colorless. Ancient Greeks thought quartz was ice that had frozen so hard it wouldn't melt, so they called it krystallos ("ice"), thereby giving us the word crystal. Yellowish citrine arises from overheated amethyst, but experts differ over what precisely gives amethyst its characteristic purple pop. Some say it's iron oxide, while others favor manganese or hydrocarbons [sources: Banfield; Encyclopaedia Britannica; Encyclopaedia Britannica].

The silica-rich mineral family, or silicates, includes tourmaline, valued both as a gemstone and for its piezoelectric properties, and beryl, a family of gems comprising aquamarine (pale blue-green), emerald (deep green), heliodor (golden yellow) and morganite (pink). The biggest crystal ever found was a beryl from Malakialina, Madagascar. It measured 59 feet (18 meters) long and 11 feet (3.5 meters) across, and weighed in at a hefty 400 tons (380,000 kilograms) [sources: Banfield; Encyclopaedia Britannica; Encyclopaedia Britannica].

Silicates are only one of several elemental crystal families. Oxides (including the aforementioned corundum) contain oxygen as a negatively charged ion; phosphates pack phosphorus; borates burst with boron (B); sulfides and sulfates seethe with sulfur; and halides hold fast to chlorine and other elements from group VIIA in the periodic table [source: Banfield].

The carbonate family contains crystals rich in carbon and oxygen. Jewelers know it best for aragonite, a calcium carbonate variety that oysters use to build pearls. Aragonite can form from either geological or biological processes [sources: Banfield; Encyclopaedia Britannica].

Last but not last, deep in the Mexican state of Chihuahua there lies a limestone cavern dubbed the Cueva de los Cristales, or Cave of Crystals, shot through with soft, transparent crystals of selenium (a type of transparent gypsum) so large (in the ballpark of 30 feet or 9 meters) they dwarf human spelunkers [source: Shea].

So what's the biggest crystal anywhere in the world? It might be in the world -- literally. According to some scientists, Earth's moon-sized inner core could be one giant iron crystal [source: Broad].

Author's Note: How are crystals made?

Self-organizing systems, from ecologies to (some say) the universe itself, are in their own way as mind-bending as chaotic ones. Indeed, some have called self-organization "anti-chaos" because, while chaos is highly sensitive to initial conditions, self-organizing systems begin with a multiplicity of initial conditions and end up in virtually the same final state.

Organization and multiplicity are what crystals are all about. They are defined by order, but not order of a single kind. Multiplicities -- of morphologies, of lattices, of polyhedra, sometimes even of crystals -- are why the same pile of atoms can give us diamonds or pencil lead. There's something sublime in that.

Related Articles

Sources

  • Arfken, George, Hans Weber and Frank Harris. "Chapter 31: Periodic Systems. Mathematical Methods for Physicists." Academic Press. Jan. 31, 2012. http://www.elsevierdirect.com/companions/9780123846549/Chap_Period.pdf
  • Banfield, Jill. "What is a Crystal?" Gem and Gem Materials. University of California, Berkeley Department of Earth and Planetary Science. http://nature.berkeley.edu/classes/eps2/wisc/Lect4.html
  • BlueDial. "About Watch Crystals." http://www.bluedial.com/crystal.htm
  • Broad, William J. "The Core of the Earth May Be a Gigantic Crystal Made of Iron." The New York Times. April 4, 1995. http://www.nytimes.com/1995/04/04/science/the-core-of-the-earth-may-be-a-gigantic-crystal-made-of-iron.html?pagewanted=all&src=pm
  • Chen, Hongbing, Congxin Ge, Rongsheng Li, Jinhao Wang, Changgen Wu and Xianling Zeng. "Growth of Lead Molybdate Crystals by Vertical Bridgman Method." Bulletin of Materials Science. Vol. 28, no. 6. Page 555. October 2005. http://www.ias.ac.in/matersci/bmsoct2005/555.pdf
  • Colorado University at Boulder Department of Chemistry and Biochemistry. "Crystallization." http://orgchem.colorado.edu/Technique/Procedures/Crystallization/Crystallization.html
  • de Dios, Angel C. "Solids and Symmetry." Georgetown University. http://bouman.chem.georgetown.edu/S02/lect30/lect30.htm
  • Dutch, Steven. "Coordination." University of Wisconsin-Green Bay. http://www.uwgb.edu/dutchs/Petrology/coordination.htm
  • Encyclopaedia Britannica. "Amethyst." http://www.britannica.com/EBchecked/topic/20466/amethyst
  • Encyclopaedia Britannica. "Amphibole." http://www.britannica.com/EBchecked/topic/21509/amphibole
  • Encyclopaedia Britannica. "Aragonite." http://www.britannica.com/EBchecked/topic/31915/aragonite
  • Encyclopaedia Britannica. "Beryl." http://www.britannica.com/EBchecked/topic/62904/beryl
  • Encyclopaedia Britannica. "Crystal." http://www.britannica.com/EBchecked/topic/145105/crystal
  • Encyclopaedia Britannica. "Igneous Rock." http://www.britannica.com/EBchecked/topic/282318/igneous-rock
  • Encyclopaedia Britannica. "Polycrystal." http://www.britannica.com/EBchecked/topic/468425/polycrystal
  • Encyclopaedia Britannica. "Quartz." http://www.britannica.com/EBchecked/topic/486427/quartz
  • Encyclopaedia Britannica. "Tourmaline." http://www.britannica.com/EBchecked/topic/600820/tourmaline
  • Fang, S. F., K. Adomi, S. Iyer, H. Morkoc, H. Zabel, C. Choi and N. Otsuka. Gallium Arsenide and Other Compound Semiconductors on Silicon. Journal of Applied Physics. Vol. 68, no. 7. Page R31. 1990.
  • Hunting, Janet. "How are Crystals Formed?" Cornell Center for Materials Research. May 19, 2005. http://www.ccmr.cornell.edu/education/ask/index.html?quid=742
  • Isaacs, Alan, John Daintith and Elizabeth Martin. "Oxford Dictionary of Science." Oxford University Press. 4th edition. 2003.
  • Kay, Robert Woodbury. "How Can You Tell If a Ruby is Real or Fake? Is There a Test I Can Do?" Cornell Center for Materials Research. Dec. 20, 2006. http://www.ccmr.cornell.edu/education/ask/index.html?quid=1195
  • Libbrecht, Kenneth G. "A Snowflake Primer." California Institute of Technology. http://www.its.caltech.edu/~atomic/snowcrystals/primer/primer.htm
  • McKenna, Phil. "Manufacturing Method Promises Cheaper Silicon Solar." MIT Technology Review. March 15, 2012. http://www.technologyreview.com/news/427225/manufacturing-method-promises-cheaper-silicon-solar/
  • Oxford Dictionaries. "Epitaxy." http://oxforddictionaries.com/definition/epitaxy
  • Piezo Institute. "Everyday Uses." http://www.piezoinstitute.com/applications/everydayuses/index.php
  • Purdue University College of Science. "Crystal Field Theory." http://chemed.chem.purdue.edu/genchem/topicreview/bp/ch12/crystal.php#8
  • Shea, Neil. "Crystal Palace." National Geographic. November 2008. http://ngm.nationalgeographic.com/2008/11/crystal-giants/shea-text
  • Smithsonian Center for Education and Museum Studies. "Minerals and Crystals." 2012. http://www.smithsonianeducation.org/educators/lesson_plans/minerals/minerals_crystals.html
  • Smithsonian Institution. "The Lemelson Center Presents: The Quartz Watch." http://invention.smithsonian.org/centerpieces/quartz/
  • University of California at Santa Barbara. "What Are Minerals, Gems and Crystals Made of?" UCSB Science Line. http://scienceline.ucsb.edu/getkey.php?key=291
  • University of Virginia. "Chapter 7: Dislocations and Strengthening Mechanisms." Intro to Scientific Engineering of Materials. http://www.virginia.edu/bohr/mse209/chapter7.htm
  • Yu, Peter and Manuel Cardona. "Fundamentals of Semiconductors: Physics and Materials Properties." Springer. 2010.
  • Zaitseva, Natalia, Leslie Carman, Andrew Glenn, Jason Newby, Michelle Faust, Sebastien Hamel, Nerine Cherepy and Stephen Payne. "Application of Solution Techniques for Rapid Growth of Organic Crystals." Journal of Crystal Growth. Vol. 314. Page 163. 2011. https://www-gs.llnl.gov/data/assets/docs/publications/application_solution_techniques.pdf

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