Systems of Crystals

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Contents || Polyhedra in the Classroom || Suzanne's Math Lessons
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[Crystallography]   [Crystal Systems]   [Paper Nets]

Type
(and Net)
Number
of Faces
Shape(s)
of Faces
Examples*
cubic (isometric)
6
all are squares
pyrite, silver, gold, diamond, garnet, galena, halite (rock salt), spinel, fluorite
tetragonal
6
4 rectangles
2 squares
right angles
zircon
orthorhombic 6
all rectangles
3 pairs of rectangles with different sizes
right angles
topaz, epsonite, barite
rhombohedral
6
rhombuses on all sides
no right angles
calcite
monoclinic
6
4 rectangles
2 parallelograms
16 right angles
8 other angles
gypsum, muscovite, azurite
triclinic
6
parallelograms
no right angles
turquoise
hexagonal
8
2 hexagons
6 rectangles
right angles
ice, apatite, emerald,
quartz, hematite


* Links to samples are to
  1. Gem Hut - Gemstones and Jewelry Settings
      Gem Hut features a collection of natural gemstones from around the world. Their goal is not only to provide gemstones for sale, but also to educate and inform the buyer. [Permission to link to the commercial pages given by André Hut.]
  2. Great South Gems and Minerals
      Great South Gems and Minerals features "the biggest and best online picture catalog of collectible minerals, gems, crystals, genuine fossils, fossil replicas, rock art, collection tools, soapstone carvings - all available through mailorder with fast, personal service." [Permission to link to the commercial pages given by David M. Nesbitt - Webmaster for Great South Gems and Minerals.]
  3. National Center for Atmospheric Research/University Corporation for Atmospheric Research/National Science Foundation.
      The National Center for Atmospheric Research is managed by the University Corporation for Atmospheric Research under the sponsorship of the National Science Foundation. It is a not-for-profit organization dedicated to furthering our understanding of the Earth's atmosphere.[Permission to link to the photos of ice given by Linda Carbone on behalf of NCAR/UCAR/NSF.]

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