Tag Archives: crystal structures

Rodalquilarite

Rodalquilarite

  • Named after its type locality, the Rodalquilar gold deposit, Almeria, Spain
  • Formula: Fe2(TeO2OH)3(TeO3)Cl
  • Space group: P-1 (No. 2)
  • Crystal system: triclinic
  • Crystal class: -1
  • Lattice parameters: a = 5.103 Å, b = 6.653 Å, c = 9.012 Å, α = 73.40, β = 78.03° γ  = 76.76°

Picture: Christian Rewitzer  | CC BY-SA-3.0


Crystal structure (click on the picture to download the VESTA file):

(K. Momma and F. Izumi, “VESTA 3 for three-dimensional visualization of crystal, volumetric and morphology data,”J. Appl. Crystallogr., 44, 1272-1276 (2011).)

 

  • FeO6 octahedra (brown)
  • TeO3 trigonal pyramids (blue)
  • Oxygen (red)
  • Hydrogen (white)
  • Chlorine (green)

For a 3D interactive version on sketchfab, see here:

https://skfb.ly/69DIu

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Jarosite – Indicator of (liquid) water on Mars

Jarosite

  • Named after its type locality, Barranco del Jaroso in the Sierra Almagrera (near Los Lobos, Cuevas del Almanzora, Almería, Spain)
  • In 2004 the Mars Exploration Rover – B found Jarosite on Mars. Because on Earth Jarosite is only formed in liquid water, this finding strongly indicates that Mars once possessed large amounts of liquid water.
  • Formula: KFe3(OH)6(SO4)2
  • Space group: R-3m (No. 166)
  • Crystal system: trigonal
  • Crystal class: -3m
  • Lattice parameters: a = b = 7.304 Å, c = 17.268 Å, αβ = 90°, γ = 120°

Picture: CC BY-SA 3.0 | Christian Rewitzer


Crystal structure (click on the picture to download the VESTA file):

(K. Momma and F. Izumi, “VESTA 3 for three-dimensional visualization of crystal, volumetric and morphology data,” J. Appl. Crystallogr., 44, 1272-1276 (2011).)

  • KO12 only very slightly distorted icosahedra (purple)
  • FeO6 octahedra (blue)
  • SO4 tetrahedra (yellow)
  • Oxygen (red)

For a 3D interactive version, see here:

https://skfb.ly/6pGuY

Hercynite – A ferro spinel

Hercynite

  • Named after the latin name Silva Hercynia of the Bohemian Forest, where this mineral was first found
  • it is a ferro spinel
  • Formula: FeAl2O4
  • Space group: Fd-3m (No. 227)
  • Crystal system: cubic
  • Crystal class: m-3m
  • Lattice parameters: a = b = c = 8.1458 Å, α = β =  γ = 90°

Picture: CC BY-SA 3.0 nl | Fred Kruijen | http://www.mindat.org/photo-73060.html

Crystal structure (click on the picture to download the VESTA file):

(K. Momma and F. Izumi, “VESTA 3 for three-dimensional visualization of crystal, volumetric and morphology data,” J. Appl. Crystallogr., 44, 1272-1276 (2011).)

  • FeO4 tetrahedra (orange)
  • Al (blue), octahedral oxide coordination environment
  • Oxygen (red)

For a 3D interactive version, see here:

https://skfb.ly/66QEE

Orange-Red like Saffron: Crocoite

Crocoite

  • The name crocoite comes from the Greek “krokos” = saffron, alluding to the saffron-orange color of its powder
  • Formula: PbCrO4
  • Space group: P21/n (No. 14)
  • Crystal system: monoclinic
  • Crystal class: 2/m
  • Lattice parameters: a = 7.127 Å, b = 7.438 Å, c = 6.799 Å, α = 90°, β = 102.43°, γ = 90°

crocoite-360746_pd

Picture: Juergen Merzhttp://www.mindat.org/photo-360746.html
(This image has been released to the public domain.)


Crystal structure (click on the pictures to download the VESTA file):

(K. Momma and F. Izumi, “VESTA 3 for three-dimensional visualization of crystal, volumetric and morphology data,” J. Appl. Crystallogr., 44, 1272-1276 (2011).)

crocoite

View along the a axis.

Gray: Pb, red: O, orange: CrO4 tetrahedra

A rare grass-green mineral: Bayldonite

Bayldonite

  • named after its discoverer, the British physicist John Balydon
  • Formula: PbCu3(AsO4)2(OH)2
  • Space group: C2/c (No. 15)
  • Crystal system: monoclinic
  • Crystal class: 2/m
  • Lattice parameters: a = 10.15 Å, b = 5.89 Å, c = 14.08 Å, β  106.1°

bayldonite-173845

Picture: Rob Lavinsky, iRocks.com – CC BY-SA 3.0

Crystal structure (click on the picture to download the VESTA file):

bayldonite

  • Cu: blue, As: green, Pb: black, O: red, H: white
  • elongated CuO6 octahedra
  • AsO4 tetrahedra
  • Pb surrounded by 7 oxygen atoms