Editing Dodecahedron (section)

====Crystal pyrite====
The name ''crystal pyrite'' comes from one of the two common [[crystal habit]]s shown by [[pyrite]] (the other one being the [[cube]]). In pyritohedral pyrite, the faces have a [[Miller index]] of (210), which means that the [[dihedral angle]] is 2·arctan(2) ≈ 126.87° and each pentagonal face has one angle of approximately 121.6° in between two angles of approximately 106.6° and opposite two angles of approximately 102.6°. The following formulas show the measurements for the face of a perfect crystal (which is rarely found in nature).

<math>\text{Height} = \frac{\sqrt{5}}{2} \cdot \text{Long side}</math>

<math>\text{Width} = \frac{4}{3} \cdot \text{Long side}</math>

<math>\text{Short sides} = \sqrt{\frac{7}{12}} \cdot \text{Long side}</math>

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{{multiple image
 | align = left  | total_width = 320
 | image1 = Pyrite-184681.jpg
 | image2 = Pyrite-193871_angles.jpg
 | footer = Natural pyrite (with face angles on the right)
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